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Title 40: Protection of Environment

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### PART 141—NATIONAL PRIMARY DRINKING WATER REGULATIONS

Section Contents 

### Subpart A

— General § 141.1 Applicability. § 141.2 Definitions. § 141.3 Coverage. § 141.4 Variances and exemptions. § 141.5 Siting requirements. § 141.6 Effective dates. Subpart B

— Maximum Contaminant Levels § 141.11 Maximum contaminant levels for inorganic chemicals. § 141.12 [Reserved] § 141.13 Maximum contaminant levels for turbidity. Subpart C

— Monitoring and Analytical Requirements § 141.21 Coliform sampling. § 141.22 Turbidity sampling and analytical requirements. § 141.23 Inorganic chemical sampling and analytical requirements. § 141.24 Organic chemicals, sampling and analytical requirements. § 141.25 Analytical methods for radioactivity. § 141.26 Monitoring frequency and compliance requirements for radionuclides in community water systems. § 141.27 Alternate analytical techniques. § 141.28 Certified laboratories. § 141.29 Monitoring of consecutive public water systems. A ppendix A to Subpart C of Part 141

—Alternative Testing Methods Approved for Analyses Under the Safe Drinking Water Act Subpart D

— Reporting and Recordkeeping § 141.31 Reporting requirements. § 141.32 [Reserved] § 141.33 Record maintenance. § 141.34 [Reserved] § 141.35 Reporting for unregulated contaminant monitoring results. Subpart E

— Special Regulations, Including Monitoring Regulations and Prohibition on Lead Use § 141.40 Monitoring requirements for unregulated contaminants. § 141.41 Special monitoring for sodium. § 141.42 Special monitoring for corrosivity characteristics. § 141.43 Prohibition on use of lead pipes, solder, and flux.

Subpart F

— Maximum Contaminant Level Goals and Maximum Residual Disinfectant Level Goals § 141.50 Maximum contaminant level goals for organic contaminants. § 141.51 Maximum contaminant level goals for inorganic contaminants. § 141.52 Maximum contaminant level goals for microbiological contaminants. § 141.53 Maximum contaminant level goals for disinfection byproducts. § 141.54 Maximum residual disinfectant level goals for disinfectants. § 141.55 Maximum contaminant level goals for radionuclides.

Subpart G

— National Primary Drinking Water Regulations: Maximum Contaminant Levels and Maximum Residual Disinfectant Levels § 141.60 Effective dates. § 141.61 Maximum contaminant levels for organic contaminants. § 141.62 Maximum contaminant levels for inorganic contaminants. § 141.63 Maximum contaminant levels (MCLs) for microbiological contaminants. § 141.64 Maximum contaminant levels for disinfection byproducts. § 141.65 Maximum residual disinfectant levels. § 141.66 Maximum contaminant levels for radionuclides. Subpart H

— Filtration and Disinfection § 141.70 General requirements. 

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### § 141.71 Criteria for avoiding filtration. § 141.72 Disinfection. § 141.73 Filtration. § 141.74 Analytical and monitoring requirements. § 141.75 Reporting and recordkeeping requirements. § 141.76 Recycle provisions. Subpart I

— Control of Lead and Copper § 141.80 General requirements. § 141.81 Applicability of corrosion control treatment steps to small, medium

- size and large water systems. § 141.82 Description of corrosion control treatment requirements. § 141.83 Source water treatment requirements. § 141.84 Lead service line replacement requirements. § 141.85 Public education and supplemental monitoring requirements. § 141.86 Monitoring requirements for lead and copper in tap water. § 141.87 Monitoring requirements for water quality parameters. § 141.88 Monitoring requirements for lead and copper in source water. § 141.89 Analytical methods. § 141.90 Reporting requirements. § 141.91 Recordkeeping requirements. Subpart J

— Use of Non

- Centralized Treatment Devices § 141.100 Criteria and procedures for public water systems using point

- of

- entry devices. § 141.101 Use of bottled water. Subpart K

—Treatment Techniques § 141.110 General requirements. § 141.111 Treatment techniques for acrylamide and epichlorohydrin. Subpart L

— Disinfectant Residuals, Disinfection Byproducts, and Disinfection Byproduct Precursors § 141.130 General requirements. § 141.131 Analytical requirements. § 141.132 Monitoring requirements. § 141.133 Compliance requirements. § 141.134 Reporting and recordkeeping requirements. § 141.135 Treatment technique for control of disinfection byproduct (DBP) precursors. Subparts M

– N [Reserved]

Subpart O

— Consumer Confidence Reports § 141.151 Purpose and applicability of this subpart. § 141.152 Effective dates. § 141.153 Content of the reports. § 141.154 Required additional health information. § 141.155 Report delivery and recordkeeping. A ppendix A to Subpart O of Part 141

— Regulated Contaminants

Subpart P

— Enhanced Filtration and Disinfection

— Systems Serving 10,000 or More People § 141.170 General requirements. § 141.171 Criteria for avoiding filtration. § 141.172 Disinfection profiling and benchmarking. § 141.173 Filtration. § 141.174 Filtration sampling requirements. § 141.175 Reporting and recordkeeping requirements. Subpart Q

— Public Notification of Drinking Water Violations § 141.201 General public notification requirements. § 141.202 Tier 1 Public Notice

— Form, manner, and frequency of notice. § 141.203 Tier 2 Public Notice

— Form, manner, and frequency of notice. § 141.204 Tier 3 Public Notice

— Form, manner, and frequency of notice. § 141.205 Content of the public notice. § 141.206 Notice to new billing units or new customers. § 141.207 Special notice of the availability of unregulated contaminant monitoring results. § 141.208 Special notice for exceedance of the SMCL for fluoride. § 141.209 Special notice for nitrate exceedances above MCL by non

- community water systems (NCWS), where granted permission by the primacy agency under §141.11(d) § 141.210 Notice by primacy agency on behalf of the public water system. § 141.211 Special notice for repeated failure to conduct monitoring of the source water for Cryptosporidium and for failure to determine bin classification or mean Cryptosporidium level. A ppendix A to Subpart Q of Part 141

— NPDWR Violations and Other Situations Requiring Public Notice 1 

### A ppendix B to Subpart Q of Part 141

— Standard Health Effects Language for Public Notification A ppendix C to Subpart Q of Part 141

— List of Acronyms Used in Public Notification Regulation Subpart R [Reserved]

Subpart S

— Ground Water Rule § 141.400 General requirements and applicability. 

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### § 141.401 Sanitary surveys for ground water systems. § 141.402 Ground water source microbial monitoring and analytical methods. § 141.403 Treatment technique requirements for ground water systems. § 141.404 Treatment technique violations for ground water systems. § 141.405 Reporting and recordkeeping for ground water systems. Subpart T

— Enhanced Filtration and Disinfection

— Systems Serving Fewer Than 10,000 People

General Requirements § 141.500 General requirements. § 141.501 Who is subject to the requirements of subpart T? § 141.502 When must my system comply with these requirements? § 141.503 What does subpart T require?

Finished Water Reservoirs § 141.510 Is my system subject to the new finished water reservoir requirements? § 141.511 What is required of new finished water reservoirs? Additional Watershed Control Requirements for Unfiltered Systems § 141.520 Is my system subject to the updated watershed control requirements? § 141.521 What updated watershed control requirements must my unfiltered system implement to continue to avoid filtration? § 141.522 How does the State determine whether my system's watershed control requirements are adequate?

Disinfection Profile § 141.530 What is a disinfection profile and who must develop one? § 141.531 What criteria must a State use to determine that a profile is unnecessary? § 141.532 How does my system develop a disinfection profile and when must it begin? § 141.533 What data must my system collect to calculate a disinfection profile? § 141.534 How does my system use this data to calculate an inactivation ratio? § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? § 141.536 My system has developed an inactivation ratio; what must we do now?

Disinfection Benchmark § 141.540 Who has to develop a disinfection benchmark? § 141.541 What are significant changes to disinfection practice? § 141.542 What must my system do if we are considering a significant change to disinfection practices? § 141.543 How is the disinfection benchmark calculated? § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? Combined Filter Effluent Requirements § 141.550 Is my system required to meet subpart T combined filter effluent turbidity limits? § 141.551 What strengthened combined filter effluent turbidity limits must my system meet? § 141.552 My system consists of “ alternative filtration ” and is required to conduct a demonstration

—what is required of my system and how does the State establish my turbidity limits? § 141.553 My system practices lime softening

— is there any special provision regarding my combined filter effluent?
Individual Filter Turbidity Requirements § 141.560 Is my system subject to individual filter turbidity requirements? § 141.561 What happens if my system's turbidity monitoring equipment fails? § 141.562 My system only has two or fewer filters

— is there any special provision regarding individual filter turbidity monitoring? § 141.563 What follow

- up action is my system required to take based on continuous turbidity monitoring? § 141.564 My system practices lime softening

— is there any special provision regarding my individual filter turbidity monitoring?
Reporting and Recordkeeping Requirements § 141.570 What does subpart T require that my system report to the State? § 141.571 What records does subpart T require my system to keep? Subpart U

— Initial Distribution System Evaluations § 141.600 General requirements. § 141.601 Standard monitoring. § 141.602 System specific studies. § 141.603 40/30 certification. § 141.604 Very small system waivers. § 141.605 Subpart V compliance monitoring location recommendations. Subpart V

— Stage 2 Disinfection Byproducts Requirements § 141.620 General requirements. § 141.621 Routine monitoring. § 141.622 Subpart V monitoring plan. § 141.623 Reduced monitoring. § 141.624 Additional requirements for consecutive systems. § 141.625 Conditions requiring increased monitoring. § 141.626 Operational evaluation levels. § 141.627 Requirements for remaining on reduced TTHM and HAA5 monitoring based on subpart L results. § 141.628 Requirements for remaining on increased TTHM and HAA5 monitoring based on subpart L results. § 141.629 Reporting and recordkeeping requirements. 

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### Subpart W

— Enhanced Treatment forCryptosporidium

General Requirements § 141.700 General requirements. Source Water Monitoring Requirements § 141.701 Source water monitoring. § 141.702 Sampling schedules. § 141.703 Sampling locations. § 141.704 Analytical methods. § 141.705 Approved laboratories. § 141.706 Reporting source water monitoring results. § 141.707 Grandfathering previously collected data. Disinfection Profiling and Benchmarking Requirements § 141.708 Requirements when making a significant change in disinfection practice. § 141.709 Developing the disinfection profile and benchmark.
Treatment Technique Requirements § 141.710 Bin classification for filtered systems. § 141.711 Filtered system additional Cryptosporidium treatment requirements. § 141.712 Unfiltered system Cryptosporidium treatment requirements. § 141.713 Schedule for compliance with Cryptosporidium treatment requirements. § 141.714 Requirements for uncovered finished water storage facilities. Requirements for Microbial Toolbox Components § 141.715 Microbial toolbox options for meeting Cryptosporidium treatment requirements. § 141.716 Source toolbox components. § 141.717 Pre

- filtration treatment toolbox components. § 141.718 Treatment performance toolbox components. § 141.719 Additional filtration toolbox components. § 141.720 Inactivation toolbox components.
Reporting and Recordkeeping Requirements § 141.721 Reporting requirements. § 141.722 Recordkeeping requirements. Requirements for Sanitary Surveys Performed by EPA § 141.723 Requirements to respond to significant deficiencies identified in sanitary surveys performed by EPA. Subpart X

—Aircraft Drinking Water Rule § 141.800 Applicability and compliance date. § 141.801 Definitions. § 141.802 Coliform sampling plan. § 141.803 Coliform sampling. § 141.804 Aircraft water system operations and maintenance plan. § 141.805 Notification to passengers and crew. § 141.806 Reporting requirements. § 141.807 Recordkeeping requirements. § 141.808 Audits and inspections. § 141.809 Supplemental treatment. § 141.810 Violations.

Authority: 42 U.S.C. 300f, 300g–1, 300g–2, 300g–3, 300g–4, 300g–5, 300g–6, 300j–4, 300j–9, and 300j–11.

Source: 40 FR 59570, Dec. 24, 1975, unless otherwise noted.

Editorial Note: Nomenclature changes to part 141 appear at 69 FR 18803, Apr. 9, 2004.


### Note: For community water systems serving 75,000 or more persons, monitoring must begin 1 year following promulation and the effective date of the MCL is 2 years following promulgation. For community water systems serving 10,000 to 75,000 persons, monitoring must begin within 3 years from the date of promulgation and the effective date of the MCL is 4 years from the date of promulgation. Effective immediately, systems that plan to make significant modifications to their treatment processes for the purpose of complying with the TTHM MCL are required to seek and obtain State approval of their treatment modification plans. This note affects §§141.2, 141.6, 141.12, 141.24 and 141.30. For additional information see 44 FR 68641, Nov. 29, 1979.
Subpart A—General

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### § 141.1 Applicability.

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This part establishes primary drinking water regulation s pursuant to section 1412 of the Public Health Service Act, as amended by the Safe Drinking W ater Act (Pub. L. 93–523); and related regulations applicable to public water systems.


### § 141.2 Definitions. 

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As used in this part, the term:

A ct means the Public Health Service Act, as amended by the Safe Drinking Water Act, Public Law 93– 523.

A ction level, is the concentration of lead or copper in water specified in §141.80(c) which determines, in some cases, the treatment requirements contained in subpart I of this part that a water system is required to complete.
Bag filters are pressure-driven separation devices that remove particulate matter larger than 1 micrometer using an engineered porous filtration media. They are ty pically constructed of a non-rigid, fabric filtration media housed in a pressure vessel in which the direction of flow is from the inside of the bag to outside.

Bank filtration is a water treatment process that uses a well to recover surface water that has naturally infiltrated into ground water through a river bed or bank(s). Infiltration is typically enhanced by the hydraulic gradient imposed by a nearby pumping water supply or other well(s).

Best available technology or BAT means the best technology, treatme nt techniques, or other means which the Administrator finds, after examination for efficacy under fiel d conditions and not solely under laboratory conditions, are available (taking cost in to consideration). For the pur poses of setting MCLs for synthetic organic chemicals, any BAT must be at l east as effective as gran ular activated carbon.
Cartridge filters are pressure-driven separati on devices that remove particulate matter larger than 1 micrometer using an engineered porous filtration media. They are typica lly constructed as rigid or semirigid, self-supporting filter elements housed in pressu re vessels in which flow is from the outside of the cartridge to the inside.
Coagulation means a process using coagul ant chemicals and mixing by which colloidal and suspended materials are destabilized and agglomerated into flocs.
Combined distribution system is the interconnected distribution sy stem consisting of the distribution systems of wholesale systems and of the cons ecutive systems that receive finished water.

Community water system means a public water system which serv es at least 15 service connections used by year-round residents or regularly serves at least 25 year-round residents.
Compliance cycle means the nine-year calendar year cycle during which public water systems must monitor. Each compliance cycle consists of three three -year compliance periods. The first calendar year cycle begins January 1, 1993 and ends December 31, 2001; the second begins January 1, 2002 and ends December 31, 2010; the third begins January 1, 2011 and ends December 31, 2019.

Compliance period means a three-year calendar year period within a compliance cycle. Each compliance cycle has three three-year compliance periods. Within the first compliance cycle, the first compliance period runs from January 1, 1993 to December 31, 1995; the second from January 1, 1996 to December 31, 1998; the third from January 1, 1999 to December 31, 2001.
Comprehensive performance evaluation (CPE) is a thorough review and analysis of a treatment plant's performance-based capabilities and associated administrative, operatio n and maintenance practices. It is conducted to identify factors that may be ad versely impacting a plant's capability to achieve compliance and emphasizes approaches that ca n be implemented without significant capital improvements. For purpose of compliance with subparts P and T of this part, the comprehensive performance evaluation must c onsist of at least the following components: Assessment of plant performance; evaluation of major unit processes; identification and priori tization of performance limiting factors; assessment of the applicability of comprehe nsive technical assistance; and preparation of a CPE report.
Confluent growth means a continuous bacterial growth covering the entire filtration area of a membrane filter, or a portion thereof, in which bacterial colonies are not discrete.
Consecutive system is a public water system that receives some or all of its finished water from one or more wholesale systems. Delivery may be through a di rect connection or throug h the distribution system of one or more consecutive systems.

Contaminant means any physical, chemical, biological, or radiological substance or matter in water.

Conventional filtration treatment means a series of processes incl uding coagulation, flocculation, sedimentation, and filtration resulting in substantial particulate removal.

Corrosion inhibitor means a substance capable of reducing the corrosivity of water toward metal plumbing materials, especially lead and copper, by for ming a protective film on the interior surface of those materials.

CT or CTcalc is the product of “residual disi nfectant concentration” (C) in mg/1 determined before or at the first customer, and the corresponding “disinfectant contact ti me” (T) in minutes, i.e. , “C” x “T”. If a public water system applies disinfectants at more than one point prior to the first customer, it must determine the CT of each disinfectant sequence before or at the first customer to determine the total percent inactivation or “total inactivation ratio.” In determining the to tal inactivation ratio, the public water system must determine the residual disinfectan t concentration of each di sinfection sequence and corresponding contact time before any subs equent disinfection application point(s). “CT 99.9 ” is the CT value required for 99.9 perc ent (3–log) i nactivation of Giardia lamblia cysts. CT 99.9 for a variety of disinfectants and conditions appear in tables 1.1–1.6, 2.1, and 3.1 of §141.74(b)(3).

is the inactivation ratio. The sum of the inactiv ation ratios, or total inac tivation ratio shown as 

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...is calculated by adding together the inactivation ratio for each disinfec tion sequence. A total inactivation ratio equal to or greater than 1.0 is assume d to provide a 3-log inactivation of Giardia lamblia cysts.

Diatomaceous earth filtration means a process resulting in substantial particulate removal in which (1) a precoat cake of diatomaceous earth filter media is deposited on a support membrance (septum), and (2) while the water is filtered by passing through the cake on the septum, additional filter media known as body feed is continuously added to the feed water to maintain the permeability of the filter cake.

Direct filtration means a series of processes including coagulation and filtration but excluding sedimentation resulting in substantial particulate removal.

Disinfectant means any oxidant, including but not limited to chlorine, chlorine dioxide, chloramines, and ozone added to water in any part of the treatment or distribution process, that is intended to kill or inactivate pathogenic microorganisms.

Disinfectant contact time (“T” in CT calculations) means the time in minutes that it takes for water to move from the point of disinfectant application or the previous point of disinfectant residual measurement to a point before or at the point wh ere residual disinfectant c oncentration (“C”) is measured. Where only one “C” is measured, “T” is the time in minutes that it takes for water to move from the point of disinfectant application to a point before or at where residual disinfectant concentration (“C”) is measured. Where more than one “C” is measured, “T” is (a) for the first measurement of “C”, the time in minutes that it takes for water to move from the first or only point of di sinfectant application to a point before or at the point where the first “C” is measured and (b) for subsequent measurements of “C”, the time in minutes that it takes for water to move from the previous “C” m easurement point to the “C” measurement point for which the particular “T” is bei ng calculated. Disinfectant co ntact time in pipelines must be calculated based on “plug flow” by dividing the internal vo lume of the pipe by the maximum hourly flow rate through that pipe. Disinfectant contacttime within mixing basins and storage reservoirs must be determined by tracer studies or an equivalent demonstration.

Disinfection means a process which inactivates pathogenic organisms in water by chemical oxidants or equivalent agents.

Disinfection profile is a summary of Giardia lamblia inactivation through the treatment plant. The procedure for developing a disinfection profile is contained in §141.172 (Disinfection profiling and benchmarking) in subpart P and §§141.530–141.536 (Disinfection profile) in subpart T of this part.

Domestic or other non-distribution system plumbing problem means a coliform contamination problem in a public water system with more than one service connec tion that is limited to the specific service connection from which the coliform-positive sample was taken.

Dose equivalent means the product of the absorbed dose from ionizing radiation and such factors as account for differences in biological effectiveness due to the type of radiation and its distribution in the body as specified by the International Commission on Radiological Units and Measurements (ICRU).

Dual sample set is a set of two samples collected at the same time and same location, with one sample analyzed for TTHM and the other sample analyzed fo r HAA5. Dual sample sets are collected for the purposes of conducting an IDSE under subpart U of this part and determining compliance with the TTHM and HAA5 MCLs under subpart V of this part.

Effective corrosion inhibitor residual, for the purpose of subpart I of thi s part only, means a concentration sufficient to form a passivating film on the interior walls of a pipe.

Enhanced coagulation means the addition of sufficient coagulant for improved removal of disinfection byproduct precursors by conventional filtration treatment.
Enhanced softening means the improved removal of disinfection byproduct precursors by precipitative softening.

Filter profile is a graphical representation of individual fi lter performance, based on continuous turbidity measurements or total particle counts versus time for an entire filter run, from startup to backwash inclusively, that includes an assessment of filter performance while another filter is being backwashed.

Filtration means a process for removing particulate matter from water by passage through porous media.

Finished water is water that is introduced i nto the distribution system of a public water system and is intended for distribution and consumption without further treatment, except as treatment necessary to maintain water quality in the distribution system (e.g., booster disinfection, addition of corrosion control chemicals).

First draw sample means a one-liter sample of tap water, collected in accordance with §141.86(b)(2), that has been standing in plumbing pipes at least 6 hours and is collected without flushing the tap.

Flocculation means a process to enhance agglomeration or collect ion of smaller floc particles into larger, more easily settleable particles through gentle stirring by hydraulic or mechanical means.

Flowing stream is a course of running water flowing in a definite channel.

GAC10 means granular activated carbon filter beds with an empty-bed contact time of 10 minutes based on average daily flow and a carbon reactivation frequency of every 180 days, except that the reactivation frequency for GAC10 used as a best available technology for compliance with subpart V MCLs under §141.64(b)(2) shall be 120 days.

GAC20 means granular activated carbon filter beds with an empty-bed contact time of 20 minutes based on average daily flow and a carbon re activation frequency of every 240 days.

Ground water under the direct influence of surface water (GWUDI) means any water beneath the surface of the ground with significant occurrence of in sects or other macroorganisms, algae, or largediameter pathogens such as Giardia lamblia or Cryptosporidium, or significant and rel atively rapid shifts in water characteristics such as turbidity, tempera ture, conductivity, or pH which closely correlate to 

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...climatological or surface water condi tions. Direct influence must be determined for individual sources in accordance with criteria established by the State. The State determination of direct influence may be based on site-specific measurements of water qua lity and/or documentation of well construction characteristics and geology with field evaluation.

Gross alpha particle activity means the total radioactivity due to alph a particle emission as inferred from measurements on a dry sample.
Gross beta particle activity means the total radioactivity due to beta particle emission as inferred from measurements on a dry sample.
Haloacetic acids (five) (HAA5) mean the sum of the concentrations in milligrams per liter of the haloacetic acid compounds (mo nochloroacetic acid, dichloroacet ic acid, trichloroacetic acid, monobromoacetic acid, and dibromoacetic acid), ro unded to two significant figures after addition.

Halogen means one of the chemical elemen ts chlorine, bromine or iodine.

Initial compliance period means the first full three-year complianc e period which begins at least 18 months after promulgation, except for contaminants li sted at §141.61(a) (19)–(21), (c) (19)–(33), and §141.62(b) (11)–(15), initial compliance period means the first full three-year compliance period after promulgation for systems with 150 or more serv ice connections (January 1993–December 1995), and first full three-year compliance period after the effective date of the regulation (January 1996–December 1998) for systems having fewer than 150 service connections.

Lake/reservoir refers to a natural or man made basin or hollow on the Earth's surface in which water collects or is stored that may or may not have a current or single direction of flow.

Large water system, for the purpose of subpart I of this part onl y, means a water system that serves more than 50,000 persons.

Lead service line means a service line made of lead which connects the water main to the building inlet and any lead pigtail, gooseneck or other fi tting which is connected to such lead line.

Legionella means a genus of bacteria, some species of wh ich have caused a type of pneumonia called Legionnaires Disease.

Locational running annual average (LRAA) is the average of sample analytical results for samples taken at a particular monitoring location durin g the previous four ca lendar quarters.

Man-made beta particle and photon emitters means all radionuclides emitting beta particles and/or photons listed in Maximum Permissible Body Burdens and Maximum Permissible Concentration of Radionuclides in Air or Water for Occupational Exposure, NBS Handbook 69, except the daughter products of thorium–232, uranium–235 and uranium–238.

Maximum contaminant level means the maximum permissable level of a contaminant in water which is delivered to any user of a public water system.

Maximum contaminant level goal or MCLG means the maximum level of a contaminant in drinking water at which no known or anticipated adverse effect on th e health of persons would occur, and which allows an adequate margin of safety. Maximum contaminant level goals are nonenforceable health goals.
Maximum residual disinfectant level (MRDL) means a level of a disinfectant added for water treatment that may not be exceeded at the consumer's tap wi thout an unacceptable possibility of adverse health effects. For chlorine and chloramines, a PWS is in co mpliance with the MRDL when the running annual average of monthly averages of samples taken in the distribution system, computed quarterly, is less than or equal to the MRDL. For chlorine dioxide, a PWS is in compliance with the MRDL when daily samples are taken at the entrance to the distribution system and no two consecutive daily samples exceed the MRDL. MRDLs are enforceable in the same manner as maximum contaminant levels under Section 1412 of the Safe Drinking Water Act. There is convincing evidence that addition of a disinfectant is necessary for control of waterborne microbial contaminants. Notwithstanding the MRDLs listed in §141.65, operators may increase residual disinfectant levels of chlorine or chloramines (but not chlorine dioxide) in the distribution system to a level and for a time necessary to protect public health to address specific microbiological contamination problems c aused by circumstances such as distribution line breaks, storm runoff events, source wate r contamination, or cross-connections.
Maximum residual disinfectant level goal (MRDLG) means the maximum level of a disinfectant added for water treatment at which no known or anticipated adv erse effect on the health of persons would occur, and which allows an adequate margin of safety. MRDLGs are nonenforceable health goals and do not reflect the benefit of the addition of the chemical for control of wa terborne microbial contaminants.
Maximum Total Trihalomethane Potential (MTP) means the maximum concentration of total trihalomethanes produced in a given water contai ning a disinfectant residual after 7 days at a temperature of 25 °C or above.

Medium-size water system, for the purpose of subpart I of this part only, means a water system that serves greater than 3,300 and less than or equal to 50,000 persons.

Membrane filtration is a pressure or vacuum driven separation process in which particulate matter larger than 1 micrometer is rejected byan engineered barrier, primarily through a size-exclusion mechanism, and which has a measurable removal efficiency of a target organism that can be verified through the application of a direct integrity test. This defi nition includes the common membrane technologies of microfiltration, ultrafiltration, nano filtration, and reverse osmosis.

Near the first service connection means at one of the 20 percent of all service connections in the entire system that are nearest the water supply treatment fa cility, as measured by water transport time within the distribution system.

Non-community water system means a public water system that is not a community water system. A non-community water system is either a “transient non-community water system (TWS)” or a “nontransient non-community water system (NTNCWS).”

Non-transient non-community water system or NTNCWS means a public water system that is not a community water system and that regu larly serves at least 25 of the same persons over 6 months per year. 

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...Optimal corrosion control treatment, for the purpose of subpart I of thi s part only, means the corrosion control treatment that minimizes the lead and copper co ncentrations at users' taps while insuring that the treatment does not cause the water system to violate an y national primary drinking water regulations.

Performance evaluation sample means a reference sample provided to a laboratory for the purpose of demonstrating that the laboratory can successfully analyze the sample within limits of performance specified by the Agency. The true value of the concentration of the reference material is unknown to the laboratory at the time of the analysis.

Person means an individual; corporation; company; asso ciation; partnership; municipality; or State, Federal, or tribal agency.
Picocurie (pCi) means the quantity of radioactive material producing 2.22 nuclear transformations per minute.

Plant intake refers to the works or structures at the head of a conduit through which water is diverted from a source (e.g., river or lake) into the treatment plant.

Point of disinfectant application is the point where the disinfectant is applied and water downstream of that point is not subject to recontamination by surface water runoff.

Point-of-entry treatment device (POE) is a treatment device applied to the drinking water entering a house or building for the purpose of reducing contam inants in the drinking water distributed throughout the house or building.
Point-of-use treatment device (POU) is a treatment device applied to a single tap used for the purpose of reducing contaminants in drinking water at that one tap.

Presedimentation is a preliminary treatment process used to remove gravel, sand and other particulate material from the source water through settling before the water enters the primary clarification and filtration processes in a treatment plant.

Public water system means a system for the provision to the public of water for human consumption through pipes or, after August 5, 1998, other constructed conveyances, if such system has at least fifteen service connections or regularly serves an aver age of at least twenty-five i ndividuals daily at least 60 days out of the year. Such term includes: any coll ection, treatment, storage, and distribution facilities under control of the oper ator of such system and used primarily in connection with such system; and any collection or pretreatment storage facilities not under su ch control which are used primarily in connection with such system. Such term does not include any “speci al irrigation district.” A public water system is either a “community water system” or a “noncommunity water system.”

Rem means the unit of dose equivalent from ionizing ra diation to the total body or any internal organ or organ system. A “millirem (mrem)” is 1/1000 of a rem.

Repeat compliance period means any subsequent compliance period after the initial compliance period.

Residual disinfectant concentration (“C” in CT calculations) means the concentration of disinfectant measured in mg/l in a representative sample of water.
Sanitary survey means an onsite review of the water source, facilities, equipment, operation and maintenance of a public water system for the purpose of evaluating the adequacy of such source, facilities, equipment, operation and maintenance forproducing and distributing safe drinking water.

Sedimentation means a process for removal of solids before filtration by gravity or separation.

Service connection, as used in the definition of public water system, does not include a connection to a system that delivers water by a c onstructed conveyance other than a pipe if:

(1) The water is used exclusivel y for purposes other than residential uses (consisting of drinking, bathing, and cooking, or other similar uses);
(2) The State determines that alternati ve water to achieve the equivalent level of public health protection provided by the applicable national primary drinking water regulation is provided for residential or similar uses for drinking and cooking; or
(3) The State determines that the water provided for re sidential or similar uses for drinking, cooking, and bathing is centrally treated or treated at the point of en try by the provider, a pass-through entity, or the user to achieve the equivalent level of protection provided by the applicable national primary drinking water regulations.

Service line sample means a one-liter sample of water collected in accordance with §141.86(b)(3), that has been standing for at least 6 hours in a service line.
Single family structure, for the purpose of subpart I of this part onl y, means a building constructed as a single-family residence that is currently used as either a residence or a place of business.

Slow sand filtration means a process involving passage of raw water through a bed of sand at low velocity (generally less than 0.4 m/h) resulting in substantial particulate removal by physical and biological mechanisms.
Small water system, for the purpose of subpart I of this part onl y, means a water system that serves 3,300 persons or fewer.
Special irrigation district means an irrigation district in existenc e prior to May 18, 1994 that provides primarily agricultural service through a piped water sys tem with only incidental residential or similar use where the system or the residential or similar users of the system comply with the exclusion provisions in section 1401(4)(B)(i)(II) or (III).

Standard sample means the aliquot of finished drinking wa ter that is examined for the presence of coliform bacteria.

State means the agency of the State or Tribal gover nment which has jurisdiction over public water systems. During any period when a State or Tribal government does not have primary enforcement 

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...responsibility pursuant to section 1413 of the Act, the term “State” means the Regional Administrator, U.S. Environmental Protection Agency.

Subpart H systems means public water systems using surface water or ground water under the direct influence of surface water as a source that are su bject to the requirements of subpart H of this part.

Supplier of water means any person who owns or operates a public water system.

Surface water means all water which is open to the atmosphere and subject to surface runoff.

SUVA means Specific Ultraviolet Absorption at 254 nano meters (nm), an indicator of the humic content of water. It is a calculated parameter obtained by dividing a sample's ultraviolet absorption at a wavelength of 254 nm (UV 254 ) (in m =1 ) by its concentration of dissol ved organic carbon (DOC) (in mg/L).
System with a single service connection means a system which supplies drinking water to consumers via a single service line.

Too numerous to count means that the total number of bacterial colonies exceeds 200 on a 47-mm diameter membrane filter used for coliform detection.
Total Organic Carbon (TOC) means total organic carbon in mg/L measured using heat, oxygen, ultraviolet irradiation, chemic al oxidants, or combinations of these oxidants that convert organic carbon to carbon dioxide, rounded to two significant figures.

Total trihalomethanes (TTHM) means the sum of the concentrati on in milligrams per liter of the trihalomethane compounds (trichloromethane [chloroform], dibromochloromethane, bromodichloromethane and tribromomethane [bromoform]), rounded to two significant figures.

Transient non-community water system or TWS means a non-community water system that does not regularly serve at least 25 of the same persons over six months per year.

Trihalomethane (THM) means one of the family of organic compounds, named as derivatives of methane, wherein three of the four hydrogen atoms in methane are each substituted by a halogen atom in the molecular structure.
Two-stage lime softening is a process in which chemical additio n and hardness precipitation occur in each of two distinct unit clarification processes in series prior to filtration.
Uncovered finished water storage facility is a tank, reservoir, or other facility used to store water that will undergo no further treatment to reduce microbial patho gens except residual disinfec tion and is directly open to the atmosphere.

Virus means a virus of fecal origin which is infectious to humans by waterborne transmission.

Waterborne disease outbreak means the significant occurrence of acute infectious illness, epidemiologically associated with the ingestion of water from a public water system which is deficient in treatment, as determined by the appropriate local or State agency.

Wholesale system is a public water system that treats source water as necessary to produce finished water and then delivers some or all of that finished water to another public water system. Delivery may be through a direct connection or through the distri bution system of one or more consecutive systems.

[40 FR 59570, Dec. 24, 1975]

Editorial Note: For Federal Register citations affecting §141.2, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.fdsys.gov.


### § 141.3 Coverage.

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This part shall apply to each public water system, unless the public water system meets all of the following conditions:
(a) Consists only of distribution and storage facilities (and does not have any collection and treatment facilities);
(b) Obtains all of its water from, but is not owned or operated by, a public water system to which such regulations apply:
(c) Does not sell water to any person; and
(d) Is not a carrier which conveys passengers in interstate commerce.


### § 141.4 Variances and exemptions.

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(a) Variances or exemptions from certain provisions of these regulations may be granted pursuant to sections 1415 and 1416 of the Act and subpart K of part 142 of this chapter (for small system variances) by the entity with primary enforcement responsibility, except that variances or exemptions from the MCL for total coliforms and variances from any of the treatment technique requirements of subpart H of this part may not be granted.
(b) EPA has stayed the effective date of this section relating to the total coliform MCL of §141.63(a) for systems that demonstrate to the State that the violatio n of the total coliform MCL is due to a persistent growth of total coliforms in the distribution system rather than fecal or pathogenic contamination, a treatment lapse or deficiency, or a problem in the operation or maintenance of the distribution system. 

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...[54 FR 27562, June 29, 1989, as amended at 56 FR 1557, Jan. 15, 1991; 63 FR 43846, Aug. 14, 1998]


### § 141.5 Siting requirements.

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Before a person may enter into a financial commitment for or initiate construction of a new public water system or increase the capacity of an existing public water system, he shall notify the State and, to the extent practicable, avoid locating part or all of the new or expanded facility at a site which:
(a) Is subject to a significant risk from earthquakes, floods, fires or other disasters which could cause a breakdown of the public water system or a portion thereof; or
(b) Except for intake structures, is within the floodplain of a 100–year fl ood or is lower than any recorded high tide where appropriate records exist. The U.S. Environmental Protection Agency will not seek to override land use decisions affecting public water systems siting which are made at the State or local government levels.


### § 141.6 Effective dates.

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(a) Except as provided in paragraphs (b) through (k) of this section, and in §141.80(a)(2), the regulations set forth in this part shall take effect on June 24, 1977.
(b) The regulations for total trihalomethanes set forth in §141.12(c) shall take effect 2 years after the date of promulgation of these regulations for comm unity water systems serving 75,000 or more individuals, and 4 years after the date of promulg ation for communities serving 10,000 to 74,999 individuals.
(c) The regulations set forth in §§141.11(d); 141.21(a), (c) and (i); 141.22(a) and (e); 141.23(a)(3) and (a)(4); 141.23(f); 141.24(e) and (f); 141.25(e); 141.27(a); 141.28(a) and (b); 141.31(a), (d) and (e); 141.32(b)(3); and 141.32(d) shall take effect immediately upon promulgation.

(d) The regulations set forth in §141.41 shall take effect 18 months from the date of promulgation. Suppliers must complete the first round of sampli ng and reporting within 12 months following the effective date.
(e) The regulations set forth in §141.42 shall take effect 18 months from the date of promulgation. All requirements in §141.42 must be completed within 12 months follo wing the effective date.
(f) The regulations set forth in §141.11(c) and §14 1.23(g) are effective May 2, 1986. Section 141.23(g) (4) is effective October 2, 1987.
(g) The regulations contained in §141.6, paragraph (c) of the table in 141.12, and 141.62(b)(1) are effective July 1, 1991. The regulations contained in §§141.11(b), 141.23, 141.24, 142.57(b), 143.4(b) (12) and (b)(13), are effective July 30, 1992. The regulations contained in the revisions to §§141.32(e) (16), (25) through (27) and (46); 141.61(c)(16); and 141.62(b)(3) are effective January 1, 1993. The effective date of regulations contained in §141.61(c) (2), (3), and (4) is postponed.
(h) Regulations for the analytic methods listed at §141.23(k)(4) for measuring antimony, beryllium, cyanide, nickel, and thallium are effective August 17, 1 992. Regulations for the analytic methods listed at §141.24(f)(16) for dichloromethane, 1,2,4-trichlorobenzene, and 1,1,2-trichloroethane are effective A ugust 17, 1992. Regulations for the analytic methods listed at §141.24(h)(12) for measuring dalapon, dinoseb, diquat, endothall, endrin, glyphosate, ox amyl, picloram, simazine, benzo(a)pyrene, di(2- ethylhexyl)adipate, di(2-ethylhexyl)phthalate, hex achlorobenzene, hexachlorocyclopentadiene, and 2,3,7,8-TCDD are effective August 17, 1992. The revision to §141.12(a) promulgated on July 17, 1992 is effective on August 17, 1992.
(i) [Reserved]

(j) The arsenic maximum contaminant levels (MCL) listed in §141.62 is effective for the purpose of compliance on January 23, 2006. Requirements relating to arsenic set forth in §§141.23(i)(4), 141.23(k) (3) introductory text, 141.23(k)(3)(ii), 141.51( b), 141.62(b), 141.62(b)(16), 141.62(c), 141.62(d), and 142.62(b) revisions in Appendix A of subpart O for the consumer confidence rul e, and Appendices A and B of subpart Q for the public notification rule are e ffective for the purpose of compliance on January 23, 2006. However, the consumer confidence rule report ing requirements relating to arsenic listed in §141.154(b) and (f) are effective for the purpose of compliance on February 22, 2002.
(k) Regulations set forth in §§141.23(i)(1), 141.23(i )(2), 141.24(f)(15), 141.24(f)(22), 141.24(h)(11), 141.24(h)(20), 142.16(e), 142.16(j), and 142.16(k) are effective for the purpose of compliance on January 22, 2004.

[44 FR 68641, Nov. 29, 1979, as amended at 45 FR 57342, Aug. 27, 1980; 47 FR 10998, Mar. 12, 1982; 51 FR 11410, Apr. 2, 1986; 56 FR 30274, July 1, 1991; 57 FR 22178, May 27, 1992; 57 FR 31838, July 17, 1992; 59 FR 34322, July 1, 1994; 61 FR 24368, May 14, 1996; 66 FR 7061, Jan. 22, 2001; 66 FR 28350, May 22, 2001]


### Subpart B—Maximum Contaminant Levels

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### § 141.11 Maximum contaminant levels for inorganic chemicals.

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(a) The maximum contaminant level for arsenic app lies only to community water systems. The analyses and determination of compliance with the 0.05 milligrams per liter maximum contaminant level for arsenic use the requirements of §141.23. 

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...(b) The maximum contaminant level for arsenic is 0.0 5 milligrams per liter for community water systems until January 23, 2006.
(c) [Reserved]
(d) At the discretion of the State, nitrate levels not to exceed 20 mg/l may be allowed in a noncommunity water system if the supplier of water de monstrates to the satisfaction of the State that:
(1) Such water will not be available to children under 6 months of age; and

(2) The non-community water system is meeting the pu blic notification requirements under §141.209, including continuous posting of the fact that nitrate leve ls exceed 10 mg/l and the potential health effects of exposure; and

(3) Local and State public health authorities will be not ified annually of nitrate levels that exceed 10 mg/l; and
(4) No adverse health effects shall result.

[40 FR 59570, Dec. 24, 1975, as amended at 45 FR 57342, Aug. 27, 1980; 47 FR 10998, Mar. 12, 1982; 51 FR 11410, Apr. 2, 1986; 56 FR 3578, Jan. 30, 1991; 56 FR 26548, June 7, 1991; 56 FR 30274, July 1, 1991; 56 FR 32113, July 15, 1991; 60 FR 33932, June 29, 1995; 65 FR 26022, May 4, 2000; 66 FR 7061, Jan. 22, 2001]


### § 141.12 [Reserved]

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### § 141.13 Maximum contaminant levels for turbidity.

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The maximum contaminant levels for turbidity are ap plicable to both community water systems and noncommunity water systems using surface water sources in whole or in part. The maximum contaminant levels for turbidity in drinking water, measured at a representative entry point(s) to the distribution system, are:

Editorial Note: At 54 FR 27527, June 29, 1989, §141.13 was amended by adding introductory text, effective December 31, 1990. However, introductory text already exists. The added text follows.

The requirements in this section apply to unfilter ed systems until December 30, 1991, unless the State has determined prior to that date, in writing pursuant to §1412(b)(7)(C)(iii), that filtration is required. The requirements in this section apply to filtered sys tems until June 29, 1993. The requirements in this section apply to unfiltered systems that the State has determined, in writing pursuant to §1412(b)(7)(C) (iii), must install filtration, until June 29, 1993, oruntil filtration is installed, whichever is later.
(a) One turbidity unit (TU) , as determined by a monthly average pu rsuant to §141.22, except that five or fewer turbidity units may be allowed if the supplier of water can demonstrate to the State that the higher turbidity does not do any of the following:
(1) Interfere with disinfection;
(2) Prevent maintenance of an effective disinfec tant agent throughout the di stribution system; or
(3) Interfere with microbiological determinations.
(b) Five turbidity units based on an average for two consecutive days pursuant to §141.22.

[40 FR 59570, Dec. 24, 1975]


### Subpart C—Monitoring and Analytical Requirements

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### § 141.21 Coliform sampling.

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(a) Routine monitoring. (1) Public water systems must collect total coliform samples at sites which are representative of water throughout the distribution system according to a written sample siting plan. These plans are subject to State review and revision.

(2) The monitoring frequency for total coliforms for co mmunity water systems is based on the population served by the system, as follows:

Total Coliform Monitoring Frequency for Community Water Systems



## Population served Minimum number of samples per month 25 to 1,000 1 

## 1 1,001 to 2,500 2 2,501 to 3,300 3 3,301 to 4,100 4 4,101 to 4,900 5 

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...1 Includes public water systems which have at least 15 service connections, butserve fewer than 25 persons.
If a community water system serving 25 to 1,000 pers ons has no history of total coliform contamination in its current configuration and a s anitary survey conducted in the pastfive years shows that the system is supplied solely by a protected groundwater sour ce and is free of sanitary defects, the State may reduce the monitoring frequency specified above, except that in no case may the State reduce the monitoring frequency to less than one sample per quarter. The State must approve the reduced monitoring frequency in writing.

(3) The monitoring frequency for total coliforms for non-community water systems is as follows:
(i) A non-community water system using only ground water (except ground water under the direct influence of surface water, as defined in §141.2) and serving 1,000 persons or fewer must monitor each calendar quarter that the system provides water to the public, except that the State may reduce this monitoring frequency, in writing, if a sanitary survey shows that the system is free of sanitary defects. Beginning June 29, 1994, the State cannot reduce the monitoring frequency for a non-community water system using only ground water (except ground water under the direct influence of surface water, as defined in §141.2) and serving 1,000 pe rsons or fewer to less than once/year.

(ii) A non-community water system using only ground water (except ground water under the direct influence of surface water, as defined in §141.2) and serving more than 1,000 persons during any month must monitor at the same frequency as a like-sized co mmunity water system, as specified in paragraph (a)(2) of this section, except the State may reduce this monitoring frequency, in writing, for any month the system serves 1,000 persons or fewer. The State cannot reduce the monitoring frequency to less than once/year. For systems using ground water under the direct influence of surface water, paragraph (a)(3)(iv) of this section applies.

(iii) A non-community water system using surface water, in total or in part, must monitor at the same frequency as a like-sized community water system, as specified in paragraph (a)(2) of this section, regardless of the number of persons it serves.
(iv) A non-community water system using ground water under the direct influence of surface water, as defined in §141.2, must monitor at the same frequen cy as a like-sized community water system, as specified in paragraph (a)(2) of this section. The system must begin monitoring at this frequency beginning six months after the State determines that th e ground water is under the direct influence of surface water.
(4) The public water system must collect samples at regular time intervals throughout the month, except that a system which uses only ground water (except ground water under the direct influence of surface water, as defined in §141.2), and serves 4,900 persons or fewer, may collect all required samples on a single day if they are taken from different sites.
(5) A public water system that uses surface water or ground water under the direct influence of surface water, as defined in §141.2, and does not practice filtr ation in compliance with Subpart H must collect at least one sample near the first service connection ea ch day the turbidity level of the source water, measured as specified in §141.74(b )(2), exceeds 1 NTU. This sample must be analyzed for the presence of total coliforms. When one or more turbid ity measurements in any day exceed 1 NTU, the system must collect this coliform sample within 24 hours of the first exceedance, unless the State determines that the system, for logist ical reasons outside the system's control, cannot have the sample 

## 4,901 to 5,800 6 5,801 to 6,700 7 6,701 to 7,600 8 7,601 to 8,500 9 8,501 to 12,900 10 12,901 to 17,200 15 17,201 to 21,500 20 21,501 to 25,000 25 25,001 to 33,000 30 33,001 to 41,000 40 41,001 to 50,000 50 50,001 to 59,000 60 59,001 to 70,000 70 70,001 to 83,000 80 83,001 to 96,000 90 96,001 to 130,000 100 130,001 to 220,000 120 220,001 to 320,000 150 320,001 to 450,000 180 450,001 to 600,000 210 600,001 to 780,000 240 780,001 to 970,000 270 970,001 to 1,230,000 300 1,230,001 to 1,520,000 330 1,520,001 to 1,850,000 360 1,850,001 to 2,270,000 390 2,270,001 to 3,020,000 420 3,020,001 to 3,960,000 450 3,960,001 or more 480 

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...analyzed within 30 hours of collection. Sample results from this coliform monitoring must be included in determining compliance with the MCL for total coliforms in §141.63.

(6) Special purpose samples, such as those taken to determine whether disi nfection practices are sufficient following pipe placement, replacement, or repair, shall not be used to determine compliance with the MCL for total coliforms in §141.63. Repeat samples taken pursuant to paragraph (b) of this section are not considered special purpose samples, and must be used to determine compliance with the MCL for total coliforms in §141.63.

(b) Repeat monitoring. (1) If a routine sample is total coliform-positive, the public water system must collect a set of repeat samples within 24 hours of being notified of the positive result. A system which collects more than one routine sample/month must collect no fewer than three repeat samples for each total coliform-positive sample found. A system which co llects one routine sample/month or fewer must collect no fewer than four repeat samples for each total coliform-positive sample found. The State may extend the 24-hour limit on a case-by-case basis if the system has a logistical problem in collecting the repeat samples within 24 hours that is beyond its control. In the case of an extension, the State must specify how much time the system has to collect the repeat samples.

(2) The system must collect at least one repeat sample from the sampling tap where the original total coliform-positive sample was taken, and at least one repeat sample at a tap within five service connections upstream and at least one repeat sample at a tap within five service connections downstream of the original sampling site. If a total coliform-positive sample is at the end of the distribution system, or one away from the end of the distribution system, the State may waive the requirement to collect at least one repeat sample upstream or downstream of the original sampling site.

(3) The system must collect all repeat samples on the same day, except that the State may allow a system with a single service connection to collect the required set of repeat samples over a four-day period or to collect a larger volume repeat sample(s) in one or more sample containers of any size, as long as the total volume collected is at least 400 ml (300 ml for systems which collect more than one routine sample/month).

(4) If one or more repeat samples in the set is total coliform-positive, the public water system must collect an additional set of repeat samples in the man ner specified in paragraphs (b) (1)–(3) of this section. The additional samples must be collected with in 24 hours of being notified of the positive result, unless the State extends the limit as provided in paragraph (b)(1) of this section. The system must repeat this process until either total coliforms are not detected in one complete set of repeat samples or the system determines that the MCL for total coliforms in §141.63 has been exceeded and notifies the State.
(5) If a system collecting fewer than five routine samples/month has one or more total coliform-positive samples and the State does not invalidate the sample(s) under paragraph (c) of this section, it must collect at least five routine samples during the ne xt month the system provides water to the public, except that the State may waive this requirement if the conditions of paragraph (b)( 5) (i) or (ii) of this section are met. The State cannot waive the requirement for a system to collect repeat samples in paragraphs (b) (1)–(4) of this section.
(i) The State may waive the requirement to collect five routine samples the next month the system provides water to the public if the State, or an agent approved by the State, performs a site visit before the end of the next month the system provides water to the public. Although a sanitary survey need not be performed, the site visit must be sufficiently detailed to allow the State to determine whether additional monitoring and/or any co rrective action is needed. The Sta te cannot approve an employee of the system to perform this site visit, even if the employee is an agent approved by the State to perform sanitary surveys.
(ii) The State may waive the requirement to coll ect five routine samples the next month the system provides water to the public if the State has dete rmined why the sample was total coliform-positive and establishes that the system has corrected the proble m or will correct the problem before the end of the next month the system serves water to the public. In this case, the State must document this decision to waive the following month's additional monitoring requi rement in writing, have it approved and signed by the supervisor of the State official who recommends su ch a decision, and make this document available to the EPA and public. The written documentation must describe the specific c ause of the total coliformpositive sample and what action the system has taken and/or will take to correct this problem. The State cannot waive the requirement to collect five routine samples the next month the system provides water to the public solely on the grounds that all repeat samples are total coliform-negative. Under this paragraph, a system must still take at least one routine sample before the end of the next month it serves water to the public and use it to determi ne compliance with the MCL for total coliforms in §141.63, unless the State has determined that the sys tem has corrected the contamination problem before the system took the set of repeat samples required in paragraphs (b) (1)–(4) of this section, and all repeat samples were total coliform-negative.

(6) After a system collects a routine sample and before it learns the results of the analysis of that sample, if it collects another routine sample(s) from wi thin five adjacent service connections of the initial sample, and the initial sample, after analysis, is found to contain total coliforms, then the system may count the subsequent sample(s) as a repeat sample instead of as a routine sample.

(7) Results of all routine and repeat samples not invalidated by the State must be included in determining compliance with the MCL for total coliforms in §141.63.
(c) Invalidation of total coliform samples. A total coliform-positive sample invalidated under this paragraph (c) does not count towards meeting the minimum monitoring requirements of this section.
(1) The State may invalidate a total coliform-positive samp le only if the conditions of paragraph (c)(1) (i), (ii), or (iii) of this section are met.
(i) The laboratory estab lishes that improper sample analysis c aused the total coliform-positive result.

(ii) The State, on the basis of the results of repeat samples collected as required by paragraphs (b) (1) through (4) of this section, determines that the total coli form-positive sample resulted from a domestic or other non-distribution system plumbing problem. The State cannot invalidate a sample on the basis of repeat sample results unless all repeat sample(s) coll ected at the same tap as the original total coliformpositive sample are also total coliform-positive, and all repeat samples collected within five serviceconnections of the original tap are total coliform-negative (e.g., a State cannot invalidate a total coliformpositive sample on the basis of repeat samples if all the repeat samples are total coliform-negative, or if the public water system has only one service connection).
(iii) The State has substantial grounds to believe that a total coliform-positive result is due to a circumstance or condition which does not reflect water quality in the distribution system. In this case, the 

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...system must still collect all repeat samples required under paragraphs (b) (1)–(4) of this section, and usethem to determine compliance with the MCL for total coliforms in §141.63. To invalidate a total coliformpositive sample under this paragraph, the decision with the rationale for the decision must be documented in writing, and approved and signed by the supervisor of the State official who recommended the decision. The State must make thi s document available to EPA and the public. The written documentation must state the specific cause of the total coli form-positive sample, and what action the system has taken, or will take, to correct this problem. The State may not invalidate a total coliform-positive sample solely on the grounds that all repeat samples are total coliform-negative.
(2) A laboratory must invalidate a total coliform sample (unless total coliforms are detected) if the sample produces a turbid culture in the absence of gas production using an analytical method where gas formation is examined (e.g., the Multiple-Tube Fermentation Technique), produces a turbid culture in the absence of an acid reaction in the Presence-Absence (P-A) Coliform Te st, or exhibits confluent growth or produces colonies too numerous to count with an analytical method using a membrane filter (e.g., Membrane Filter Technique). If a laboratory inva lidates a sample because of such interference, the system must collect another sample from the same location as the original sample within 24 hours of being notified of the interference problem, and have itanalyzed for the presence of total coliforms. The system must continue to re-sample within 24 hours and have the samples analyzed until it obtains a valid result. The State may waive the 24-hour time limit on a case-by-case basis.
(d) Sanitary surveys. (1)(i) Public water systems which do not collect five or more routine samples/month must undergo an initial sanitary survey by June 29, 1994, for community public water systems and June 29, 1999, for non-community water systems. Thereafter, systems must undergo another sanitary survey every five years, except that non-community water systems using only protec ted and disinfected ground water, as defined by the State, must undergo subsequ ent sanitary surveys at leas t every ten years after the initial sanitary survey. The State must reviewthe results of each sanitary survey to determine whether the existing monitoring frequency is adequate and what additional measures, if any, the system needs to undertake to improve drinking water quality.
(ii) In conducting a sanitary surveyof a system using ground water in a State having an EPA-approved wellhead protection program under section 1428 of the Safe Drinking Water Act, information on sources of contamination within the delineated wellhead pro tection area that was collected in the course of developing and implementing the program should be co nsidered instead of collecting new information, if the information was collected since the last time the system was subject to a sanitary survey.
(2) Sanitary surveys must be performed by the State or an agent approved by the State. The system is responsible for ensuring the survey takes place.
(3) Sanitary surveys conducted by the State under the provisions of §142.16(o)(2) of this chapter may be used to meet the sanitary survey requirements of this section.
(e) Fecal coliforms/Escherichia coli (E. coli) testing. (1) If any routine or repeat sample is total coliformpositive, the system must analyze that total colifor m-positive culture medium to determine if fecal coliforms are present, except that the system may test for E. coli in lieu of fecal coliforms. If fecal coliforms or E. coli are present, the system must notify the State by the end of the day when the system is notified of the test result, unless the system is noti fied of the result after the State office is closed, in which case the system must notify the S tate before the end of the next business day.
(2) The State has the discretion to allow a public water system, on a case-by-case basis, to forgo fecal coliform or E. coli testing on a total coliform-positive sample if that system assumes that the total coliform-positive sample is fecal coliform-positive or E. coli -positive. Accordingly, the system must notify the State as specified in paragraph (e)(1) of this section and the provisions of §141.63(b) apply.
(f) Analytical methodology. (1) The standard sample volume re quired for total coliform analysis, regardless of analytical method used, is 100 ml.

(2) Public water systems need only determine the presence or absence of total coliforms; a determination of total coliform density is not required.

(3) Public water systems must conduct total coliform analyses in accordance with one of the analytical methods in the following table or one of the alternative methods listed in appendix A to subpart C of this part.

The procedures shall be done in accordance with the documents listed below. The incorporation by reference of the following documents listed in footnotes 1, 6, 8, 9, 10 , 11, 13, 14 and 15 was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the documents may be obtained from the sources listed below. Information regarding obtaining these documents can be obtained from the Safe Drinking Water Hotline at 800–426–4791. Documents may be inspected at EPA's Drinking Water Docket, EPA We st, 1301 Constitution Avenue, NW., EPA West, Room B102, Washington DC 20460 (Telephone: 202–566–2426); or at the National Archives and



## Organism Methodology 12 

## Citation 1 

## Total Coliforms 2 

## Total Coliform Ferme ntation Technique 3,4,5 

## 9221A, B.

Total Coliform Membrane Filter Technique 6 

## 9222A, B, C. Presence-Absence (P-A) Coliform Test 5,7 

## 9221D.
ONPG-MUG Test 8 

## 9223.
Colisure Test. 9


## E*Colite ®

## Test. 10


## m-ColiBlue24 ®

## Test. 11 

## Readycult® 

## Coliforms 100 Presence/Absence Test. 13 

## Membrane Filter Technique using Chromocult® 

## Coliform Agar. 14 

## Colitag ®

## Test. 15 

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...Records Administration (NARA). For information on the av ailability of this material at NARA, call 202– 741–6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

1 Standard Methods for the Examination of Water and Wastewater, 18th edition (1992), 19th edition (1995), or 20th edition (1998). American PublicHealth Association, 1015 Fifteenth Street, NW., Washington, DC 20005. The cited methods published in any of these three editions may be used. In addition, the following online vers ions may also be used: 9221 A, B, D–99, 9222 A, B, C–97, and 9223 B–97. Standard Methods Online are available at http://www.standardmethods.org. The year in which each method was approved by the Standard Methods Co mmittee is designated by the last two digits in the method number. The methods listed are the only Online versions that may be used.

2 The time from sample collection to initiation of analysis may not exceed 30 hours. Systems are encouraged but not required to hold samples below 10 deg. C during transit.

3 Lactose broth, as commercially available, may be used in lieu of lauryl tryptose broth, if the system conducts at least 25 parallel tests between this medium and lauryl tryptose broth using the water normally tested, and this comparison demonstrates th at the false-positive rate and false-negative rate for total coliform, using lactose broth, is less than 10 percent.

4 If inverted tubes are used to detect gas producti on, the media should cover these tubes at least onehalf to two-thirds after the sample is added.

5 No requirement exists to run the completed phase on 10 percent of all total coliform-positive confirmed tubes.

6 MI agar also may be used. Preparation and use of MI a gar is set forth in the article, “New medium for the simultaneous detection of total coliform and Escherichia coli in water” by Brenner, K.P., et. al., 1993, A ppl. Environ. Microbiol. 59:3534–3544. Also available from the Office of Water Resource Center (RC– 4100T), 1200 Pennsylvania Avenue, NW., Washington, DC 20460, EPA/600/J–99/225. Verification of colonies is not required.

7 Six-times formulation strength may be used if the medium is filter-sterilized rather than autoclaved.

8 The ONPG-MUG Test is also known as the Autoanalysis Collect System.

9 A description of the Colisure Test, Feb 28, 1994, may be obtained from IDEXX Laboratories, Inc., One IDEXX Drive, Westbrook, Maine 04092. The Colisure Test may be read after an incubation time of 24 hours.

10 A description of the E*Colite ®Test, “Presence/Absence for Coliforms and E. Coli in Water,” Dec 21, 1997, is available from Charm Sciences, Inc ., 36 Franklin Street, Malden, MA 02148–4120.

11 A description of the m-ColiBlue24 ®Test, Aug 17, 1999, is available from the Hach Company, 100 Dayton Avenue, Ames, IA 50010.

12 EPA strongly recommends that laboratories evaluate the false-positive and negative rates for the method(s) they use for monitoring total coliforms. EPA also encourages laboratories to establish falsepositive and false-negative rates wi thin their own laboratory and sample matrix (drinking water or source water) with the intent that if the method they choose has an unacceptable false-positive or negative rate, another method can be used. The Agency suggests that laboratories perform these studies on a minimum of 5% of all total coliform-positiv e samples, except for those methods where verification/confirmation is al ready required, e.g., the M-Endo and LES Endo Membrane Filter Tests, Standard Total Coliform Fermentation Technique, and Presence-Absence Coliform Test. Methods for establishing false-positive and negative-rates may be based on lactose fermentation, the rapid test for β

galactosidase and cytochrome oxidas e, multi-test identification sy stems, or equivalent confirmation tests. False-positive and false-negative information is often available in published studies and/or from the manufacturer(s).

13 The Readycult® Coliforms 100 Presence/Absence Te st is described in the document, “Readycult® Coliforms 100 Presence/Absence Test for Detec tion and Identification of Coliform Bacteria and Escherichla coli in Finished Waters”, November 2000, Vers ion 1.0, available from EM Science (an affiliate of Merck KGgA, Darmstadt Germany), 480 S. Democrat Road, Gibbstown, NJ 08027–1297. Telephone number is (800) 222–0342, e-mail address is: adellenbusch@emscience.com.

14 Membrane Filter Technique using Chromocult® Coliform Agar is described in the document, “Chromocult® Coliform Agar Presence/Absence Membrane Filter Test Method for Detection and Identification of Coliform Bacteria and Escherichla coli in Finished Waters”, November 2000, Version 1.0, available from EM Science (an affiliate of Merck KGgA, Darmstadt Germany), 480 S. Democrat Road, Gibbstown, NJ 08027–1297. Telephone number is (800) 222–0342, e-mail address is: adellenbusch@emscience.com.

15 Colitag ® product for the determination of the presence/absence of total coliforms and E. coli is described in “Colitag ® Product as a Test for Detection and Identification of Coliforms and E. coli Bacteria in Drinking Water and Source Water as Required in National Primary Drinking Water Regulations,” A ugust 2001, available from CPI International, Inc ., 5580 Skylane Blvd., Santa Rosa, CA, 95403, telephone (800) 878–7654, Fax (707) 545–7901, Internet address http://www.cpiinternational.com.

(4) [Reserved]
(5) Public water systems must conduct fecal coliform analysis in accordance with the following procedure. When the MTF Technique or Presence-Absence (PA) Coliform Test is used to test for total coliforms, shake the lactose-positive presumptive tube or P-A vigorously and transfer the growth with a sterile 3-mm loop or sterile applicator stick into brilliant green lactose bile broth and EC medium to determine the presence of total and fecal coliforms, respectively. For EPA-appro ved analytical methods which use a membrane filter, transfer the total colifor m-positive culture by one of the following methods: remove the membrane containing the total coliform coloni es from the substrate wi th a sterile forceps and carefully curl and insert the membrane into a tube of EC medium (the laboratory may first remove a small portion of selected colonies for verification), swab the entire membrane filter surface with a sterile cotton swab and transfer the inoculum to EC medium (do not leave the cotton swab in the EC medium), or inoculate individual total colifor m-positive colonies into EC Medium. Gently shake the inoculated tubes of EC medium to insure adequate mixing and incubate in a waterbath at 44.5 ±0.2 °C for 24 ±2 hours. 

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...Gas production of any amount in the inner fermentation tu be of the EC medium indicates a positive fecal coliform test. The preparation of EC medium is descr ibed in Method 9221E (paragraph 1a) in Standard Methods for the Examination of Wate r and Wastewater, 18th edition (1992), 19th edition (1995), and 20th edition (1998); the cited method in any one of these three editions may be used. Public water systems need only determine the presence or abse nce of fecal coliforms; a determination of fecal coliform density is not required.
(6) Public water systems must conduct analysis of Escherichia coli in accordance with one of the following analytical methods or one of the alternative methods listed in appendix A to subpart C of this part.
(i) EC medium supplemented with 50 μg/mL of 4-m ethylumbelliferyl-beta-D-glucuronide (MUG) (final concentration), as described in Method 9222G in S tandard Methods for the Examination of Water and Wastewater, 19th edition (1995) and 20th edition (1998) . Either edition may be used. Alternatively, the 18th edition (1992) may be used if at least 10 mL of EC medium, as described in paragraph (f)(5) of this section, is supplemented with 50 μg/mL of MUG before autoclaving. The inner inverted fermentation tube may be omitted. If the 18th edition is used, appl y the procedure in paragraph (f)(5) of this section for transferring a total coliform-pos itive culture to EC medium supplemented with MUG, incubate the tube at 44.5 ±0.2 °C for 24 ±2 hours, and then observe fluorescence with an ultraviolet light (366 nm) in the dark. If fluorescence is visible, E. coli are present.
(ii) Nutrient agar supplemented with 100 μg/mL of 4-methylumbelliferyl-beta-D-glucuronide (MUG) (final concentration), as described in Method 9222G in S tandard Methods for the Examination of Water and Wastewater, 19th edition (1995) and 20th edition (1998). Either edition may be used for determining if a total coliform-positive sample, as determined by a membrane filter technique, contains E. coli. A lternatively, the 18th edition (1992) may be used if the membrane filter containing a total coliformpositive colony(ies) is transferred to nutrient agar, as described in Method 9221B (paragraph 3) of Standard Methods (18th edition), supplemented with 100 μg/mL of MUG. If the 18th edition is used, incubate the agar plate at 35 °C for 4 hours and then observe the colony(ies) under ultraviolet light (366 nm) in the dark for fluorescence. If fluorescence is visible, E. coli are present.
(iii) Minimal Medium ONPG-MUG (MMO-MUG) Test, as set forth in the article “National Field Evaluation of a Defined Substrate Method for the Simult aneous Detection of Total Coliforms and Escherichia coli from Drinking Water: Comparison with Presence-Absence Techni ques” (Edberg et al.), Applied and Environmental Microbiology, Volume 55, pp. 1003 –1008, April 1989. (Note: The Autoanalysis Colilert System is an MMO-MUG test). If the MMO-MUG test is total coliform-positive after a 24-hour incubation, test the medium for fluorescence with a 366-nm ultraviolet light (preferably with a 6-watt lamp) in the dark. If fluorescence is observed, the sample is E. coli -positive. If fluorescence is questionable (cannot be definitively read) after 24 hours incubation, incubate the culture for an additional four hours (but not to exceed 28 hours total), and again test the medium for fluorescence. The MMO-MUG Test with hepes buffer in lieu of phosphate buffer is the only approved formulation for the detection of E. coli.
(iv) The Colisure Test. A description of the Colisure Test may be obtained from the Millipore Corporation, Technical Services Department, 80 Ashby Road, Bedford, MA 01730.
(v) The membrane filter method with MI agar, a descri ption of which is cited in footnote 6 to the table in paragraph (f)(3) of this section.

(vi) E*Colite ®Test, a description of which is cited in footnote 10 to the table at paragraph (f)(3) of this section.

(vii) m-ColiBlue24 ®Test, a description of which is cited in footnote 11 to the table in paragraph (f)(3) of this section.

(viii) Readycult® Coliforms 100 Presence/Absence Test, a descr iption of which is cited in footnote 13 to the table at paragraph (f)(3) of this section.

(ix) Membrane Filter Technique using Chromocult® Coliform Agar, a description of which is cited in footnote 14 to the table at paragraph (f)(3) of this section.

(x) Colitag ® , a description of which is cited in footnote 15 to the table at paragraph (f)(3) of this section.
(7) As an option to paragraph (f)(6)(iii) of this section, a system with a total coliform-positive, MUGnegative, MMO-MUG test may further analyze the culture for the presence of E. coli by transferring a 0.1 ml, 28-hour MMO-MUG culture to EC Medium + MUG with a pipet. The formulation and incubation conditions of EC Medium + MUG, and observation of the results are described in paragraph (f)(6)(i) of this section.
(8) The following materials are incorporated by referenc e in this section with the approval of the Director of the Federal Register in accordance with 5 U.S.C. 552( a) and 1 CFR part 51. Copies of the analytical methods cited in Standard Methods for the Examinati on of Water and Wastewater (18th, 19th, and 20th editions) may be obtained from the American Public Health Association et al. ; 1015 Fifteenth Street, NW., Washington, DC 20005–2605. Copies of the MMO-MUG Test, as set forth in the article “National Field Evaluation of a Defined Substrate Method forthe Simultaneous Enumeration of Total Coliforms and Escherichia coli from Drinking Water: Compar ison with the Standard Multiple Tube Fermentation Method” (Edberg et al. ) may be obtained from the American Water Works Association Research Foundation, 6666 West Quincy Avenue, Denver, CO 80235. Copies of the MMO-MUG Test as set forth in the article “National Field Evaluation of a Defined Substrate Method for the Simultaneous Enumeration of Total Coliforms and Escherichia coli from Drinking Water: Comparison with the Standard Multiple Tube Fermentation Method” (Edberg et al. ) may be obtained from the American Water Works Association Research Foundation, 6666 West Quincy Avenue, Denver, CO 80235. A description of the Colisure Test may be obtained from the Millipore Corp., Technical Services Department, 80 Ashby Road, Bedford, MA 01730. Copies may be inspected at EPA's Drinking Water Docket; 401 M St., SW.; Washington, DC 20460, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202–741–6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(g) Response to violation. (1) A public water system which has exceeded the MCL for total coliforms in §141.63 must report the violation to the State no later than the end of the next business day after it learns of the violation, and notify the public in accordance with subpart Q.

(2) A public water system which has failed to comply with a coliform monitoring requirement, including the sanitary survey requirement, must report the mo nitoring violation to the St ate within ten days after the system discovers the violation, and notify the public in accordance with subpart Q. 

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...[54 FR 27562, June 29, 1989]

Editorial Note: For Federal Register citations affecting §141.21, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.fdsys.gov.


### § 141.22 Turbidity sampling and analytical requirements.

top
The requirements in this section apply to unfilter ed systems until December 30, 1991, unless the State has determined prior to that date, in writing pursuant to section 1412(b)(7)(iii), that filtration is required. The requirements in this section apply to filtered systems until June 29, 1993. The requirements in this section apply to unfiltered systems that the State has de termined, in writing pursuant to section 1412(b) (7)(C)(iii), must install filtration, until June 29, 1993, or until filtration is installed, whichever is later.
(a) Samples shall be taken by suppliers of water forboth community and non-community water systems at a representative entry point(s) to the water distribution system at leas t once per day, for the purposes of making turbidity measurements to determine comp liance with §141.13. If the State determines that a reduced sampling frequency in a non-community will n ot pose a risk to public health, it can reduce the required sampling frequency. The option of reducing the turbidity frequency shall be permitted only in those public water systems that practice disinfection and which maintain an active residual disinfectant in the distribution system, and in those cases where the State has indicated in writing that no unreasonable risk to health existed under the circumst ances of this option. Turbidity measurements shall be made as directed in §141.74(a)(1).

(b) If the result of a turbidity analysis indicates th at the maximum allowable limit has been exceeded, the sampling and measurement shall be confirmed by re sampling as soon as practicable and preferably within one hour. If the repeat sample confirms that the maximum allowable limit has been exceeded, the supplier of water shall report to the State within 48 hours. The repeat sample shall be the sample used for the purpose of calculating the monthly averag e. If the monthly average of the daily samples exceeds the maximum allowable limit, or if the average of tw o samples taken on consecut ive days exceeds 5 TU, the supplier of water shall report to the State and notifythe public as directed in §141.31 and subpart Q.

(c) Sampling for non-community water systems shall begin within two years after the effective date of this part.
(d) The requirements of this §141.22 shall apply onlyto public water systems which use water obtained in whole or in part from surface sources.
(e) The State has the authority to determine compliance or initiate enforcement action based upon analytical results or other information compiled by their sanctioned representatives and agencies.

[40 FR 59570, Dec. 24, 1975, as amended at 45 FR 57344, Aug. 27, 1980; 47 FR 8998, Mar. 3, 1982; 47 FR 10998, Mar. 12, 1982; 54 FR 27527, June 29, 1989; 59 FR 62466, Dec. 5, 1994; 65 FR 26022, May 4, 2000]


### § 141.23 Inorganic chemical sampling and analytical requirements.

top
Community water systems shall conduct monito ring to determine compliance with the maximum contaminant levels specified in §141.62 in accordan ce with this section. Non-transient, non-community water systems shall conduct monitoring to determi ne compliance with the maximum contaminant levels specified in §141.62 in accordance with this secti on. Transient, non-community water systems shall conduct monitoring to determine compliance with the nitrate and nitrite maximum contaminant levels in §§141.11 and 141.62 (as appropriate) in accordance with this section.
(a) Monitoring shall be conducted as follows:

(1) Groundwater systems shall take a minimum of one sample at every entry point to the distribution system which is representative of each well after tr eatment (hereafter called a sampling point) beginning in the initial compliance period. The system shall take each sample at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.
(2) Surface water systems shall take a minimum of one sample at every entry point to the distribution system after any application of treatment or in the di stribution system at a point which is representative of each source after treatment (hereafter called a sampling point) beginning in the initial compliance period. The system shall take each sample at the sa me sampling point unless conditions make another sampling point more representative of each source or treatment plant.


### Note: For purposes of this paragraph, surface water systems include systems with a combination of surface and ground sources.

(3) If a system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry po int to the distribution system during periods of normal operating conditions ( i.e. , when water is representative of all sources being used).
(4) The State may reduce the total number of samples which must be analyzed by allowing the use of compositing. Composite samples from a maximum of five samples are allowed, provided that the detection limit of the method used for analysis is le ss than one-fifth of the MCL. Compositing of samples must be done in the laboratory.
(i) If the concentration in the composite sample is greater than or equal to one-fifth of the MCL of any inorganic chemical, then a follow-up sample must be taken within 14 days at each sampling point included in the composite. These samples must be analyzed for the contaminants which exceeded onefifth of the MCL in the composite sample. Detection limit s for each analytical method and MCLs for each inorganic contaminant are the following:

Detection Limits for Inorganic Contaminants



## MCL Detection limit 

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...1 MFL = million fibers per liter >10 μm. 

## Contaminant (mg/l) Methodology (mg/l) Antimony 0.006 Atomic Absorption; Furnace 0.003 Atomic Absorption; Platform 0.0008 5 

## ICP-Mass Spectrometry 0.0004 Hydride-Atomic Absorption 0.001 Arsenic 0.010 6 

## Atomic Absorption; Furnace 0.001 Atomic Absorption; Platform— Stabilized Temperature 0.0005 7


## Atomic Absorption; Gaseous Hydride 0.001
ICP-Mass Spectrometry 0.0014 8 

## Asbestos 7 MFL 1 

## Transmission Electron Microscopy 0.01 MFL Barium 2 Atomic Absorption; furnace technique 0.002
Atomic Absorption; direct aspiration 0.1 Inductively Coupled Plasma 0.002 (0.001) Beryllium 0.004 Atomic Abso rption; Furnace 0.0002 Atomic Absorption; Platform 0.00002 5 

## Inductively Coupled Plasma 2 

## 0.0003 ICP-Mass Spectrometry 0.0003 Cadmium 0.005 Atomic Absorption; furnace technique 0.0001
Inductively Coupled Plasma 0.001 Chromium 0.1 Atomic Absorption; furnace technique 0.001
Inductively Coupled Plasma 0.007 (0.001) Cyanide 0.2 Distillation, Spectrophotometric 3 

## 0.02 Distillation, Automated, Spectrophotometric 3 

## 0.005

Distillation, Amenable, Spectrophotometric 4 

## 0.02

Distillation, Selective Electrode 3, 4 

## 0.05 UV, Distillation, Spectrophotometric 9 

## 0.0005 Micro Distillation, Flow Injection, Spectrophotometric 3 

## 0.0006

Ligand Exchange with Amperometry 4 

## 0.0005
Mercury 0.002 Manual Cold Vapor Technique 0.0002 Automated Cold Vapor Technique 0.0002 Nickel xl Atomic Absorption; Furnace 0.001 Atomic Absorption; Platform 0.0006 5 

## Inductively Coupled Plasma 2 

## 0.005 ICP-Mass Spectrometry 0.0005 Nitrate 10 (as N) Manual Cadmium Reduction 0.01
Automated Hydrazine Reduction 0.01 Automated Cadmium Reduction 0.05 Ion Selective Electrode 1 Ion Chromatography 0.01 Capillary Ion Electrophoresis 0.076 Nitrite 1 (as N) Spectrophotometric 0.01 Automated Cadmium Reduction 0.05 Manual Cadmium Reduction 0.01 Ion Chromatography 0.004 Capillary Ion Electrophoresis 0.103 Selenium 0.05 Atomic Absorption; furnace 0.002 Atomic Absorption; gaseous hydride 0.002 Thallium 0.002 Atomic Absorption; Furnace 0.001 Atomic Absorption; Platform 0.0007 5 

## ICP-Mass Spectrometry 0.0003 

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...2 Using a 2X preconcentration step as noted in Method 200.7. Lower MDLs may be achieved when using a 4X preconcentration.

3 Screening method for total cyanides.

4 Measures “free” cyanides when distillation, digestion, or ligand exchange is omitted.

5 Lower MDLs are reported using stabilized te mperature graphite furnace atomic absorption.

6 The value for arsenic is effective January 23, 2006. Unit then, the MCL is 0.05 mg/L.

7 The MDL reported for EPA method 200.9 (Atomic Absorption; Platform—Stablized Temperature) was determined using a 2x conc entration step during sample digestion. The MDL determined for samples analyzed using direct analyses ( i.e. , no sample digestion) will be higher. Using multiple depositions, EPA 200.9 is capable of obtaining MDL of 0.0001 mg/L.

8 Using selective ion monitoring, EPA Method 200.8 (ICP-MS) is capable of obtaining a MDL of 0.0001 mg/L.

9 Measures total cyanides when UV-dig estor is used, and “free” cyanide s when UV-digestor is bypassed.
(ii) If the population served by the system is >3,300 persons, then compositing may only be permitted by the State at sampling points within a single system. In systems serving ≤ 3,300 persons, the State may permit compositing among di fferent systems provided the 5-sample limit is maintained.
(iii) If duplicates of the original sample taken from ea ch sampling point used in the composite sample are available, the system may use these instead of resampling. The duplicates must be analyzed and the results reported to the State within 14 days after comp leting analysis of the composite sample, provided the holding time of the sample is not exceeded.
(5) The frequency of monitoring for asbestos shall be in accordance with paragraph (b) of this section: the frequency of monitoring for antimony, arsenic, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, se lenium and thallium shall be in accordan ce with paragraph (c) of this section; the frequency of monitoring for nitrate shall be in accordance with paragraph (d) of this section; and the frequency of monitoring for nitrite shall be in accordance with paragraph (e) of this section.
(b) The frequency of monitoring conducted to de termine compliance with the maximum contaminant level for asbestos specified in §1 41.62(b) shall be conducted as follows:

(1) Each community and non-transient, non-community water system is required to monitor for asbestos during the first three-year compliance period of each nine-year compliance cycle beginning in the compliance period starting January 1, 1993.
(2) If the system believes it is not vulnerable to either asbestos contamination in its source water or due to corrosion of asbestos-cement pipe, or both, it ma y apply to the State for a waiver of the monitoring requirement in paragraph (b)(1) of this section. If the State grants the waiver, the system is not required to monitor.
(3) The State may grant a waiver based on a consideration of the following factors:
(i) Potential asbestos contamination of the water source, and

(ii) The use of asbestos-cement pipe for finished water distribution and the corrosive nature of the water.
(4) A waiver remains in effect until the completion of the three-year compliance period. Systems not receiving a waiver must monitor in accordance with the provisions of paragraph (b)(1) of this section.
(5) A system vulnerable to asbestos contamination due so lely to corrosion of as bestos-cement pipe shall take one sample at a tap served by asbestos-c ement pipe and under condi tions where asbestos contamination is most likely to occur.
(6) A system vulnerable to asbestos contaminati on due solely to source water shall monitor in accordance with the provision of paragraph (a) of this section.

(7) A system vulnerable to asbestos contamination due both to its source water supply and corrosion of asbestos-cement pipe shall take one sample at a tap served by asbestos-cement pipe and under conditions where asbestos contamination is most likely to occur.
(8) A system which exceeds the maximum contaminant levels as determined in §141.23(i) of this section shall monitor quarterly beginning in the next quarter after the violation occurred.
(9) The State may decrease the quarterly monito ring requirement to the frequency specified in paragraph (b)(1) of this section provided the State has determined that the system is reliably and consistently below the maximum contaminant level. In no case can a State make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface (or combined surface/ground) water system takes a minimum of four quarterly samples.
(10) If monitoring data collected after January 1, 1990 are generally consistent with the requirements of §141.23(b), then the State may allow systems to use that data to satisfy the monitoring requirement for the initial compliance period beginning January 1, 1993.
(c) The frequency of monitoring conducted to determ ine compliance with the maximum contaminant levels in §141.62 for antimony, arsenic, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium and thallium shall be as follows:
(1) Groundwater systems shall take one sample at each sampling point during each compliance period. Surface water systems (or combined surface/ground) shall take one sample annually at each sampling point.
(2) The system may apply to the State for a waiver from the monitoring frequencies specified in 

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...paragraph (c)(1) of this section. States may grant a public water system a waiver for monitoring of cyanide, provided that the State determines that the system is not vulnerable due to lack of any industrial source of cyanide.

(3) A condition of the waiver shall require that a system shall take a minimum of one sample while the waiver is effective. The term during which the waiver is effective shall not exceed one compliance cycle ( i.e. , nine years).
(4) The State may grant a waiver provided surface water systems have monitored annually for at least three years and groundwater systems have cond ucted a minimum of three rounds of monitoring. (At least one sample shall have been taken since Janu ary 1, 1990). Both surface and groundwater systems shall demonstrate that all previous analytical results were less than the maximum contaminant level. Systems that use a new water source are not eligible for a waiver until three rounds of monitoring from the new source have been completed.
(5) In determining the appropriate reduced monitoring frequency, the State shall consider:
(i) Reported concentrations from all previous monitoring;
(ii) The degree of variation in reported concentrations; and
(iii) Other factors which may affect contaminant co ncentrations such as changes in groundwater pumping rates, changes in the system's configuration, changes in the system's operating procedures, or changes in stream flows or characteristics.
(6) A decision by the State to grant a waiver shall be made in writing and shall set forth the basis for the determination. The determination may be initiated by the State or upon an application by the public water system. The public water system shall specify the basis for its request. The State shall review and, where appropriate, revise its determination of the appropriate monitoring frequency when the system submits new monitoring data or when other data relevant to the system's appropriate monitoring frequency become available.
(7) Systems which exceed the maximum contaminant le vels as calculated in §141.23(i) of this section shall monitor quarterly beginning in the next quarter after the violation occurred.
(8) The State may decrease the quarterly monitori ng requirement to the frequencies specified in paragraphs (c)(1) and (c)(2) of this section provi ded it has determined that the system is reliably and consistently below the maximum contaminant level. In no case can a State make this determination unless a groundwater system takes a minimum of two quarterly samples and a surface water system takes a minimum of four quarterly samples.
(9) All new systems or systems that use a new source of water that begin operation after January 22, 2004 must demonstrate compliance with the MCL within a period of time specified by the State. The system must also comply with the initial sampling fr equencies specified by the State to ensure a system can demonstrate compliance with the MCL. Routine and increased monitoring frequencies shall be conducted in accordance with the requirements in this section.
(d) All public water systems (community; non-tran sient, non-community; and transient, non-community systems) shall monitor to determine compliance with the maximum contaminant level for nitrate in §141.62.
(1) Community and non-transient, non-community wa ter systems served by groundwater systems shall monitor annually beginning January 1, 1993; systems se rved by surface water shall monitor quarterly beginning January 1, 1993.
(2) For community and non-transient, non-communitywater systems, the repeat monitoring frequency for groundwater systems shall be quarterly for at leas t one year following any one sample in which the concentration is ≥ 50 percent of the MCL. The State may allow a groundwater system to reduce the sampling frequency to annually after four consecutive quarterly samples are reliably and consistently less than the MCL.

(3) For community and non-transient, non-communitywater systems, the State may allow a surface water system to reduce the sampling frequency to annually if all analytical results from four consecutive quarters are <50 percent of the MCL. A surface water system shall return to quarterly monitoring if any one sample is ≥ 50 percent of the MCL.

(4) Each transient non-community water system sh all monitor annually beginning January 1, 1993.
(5) After the initial round of quarterly sampling is completed, each community and non-transient noncommunity system which is monitoring annually shall take subsequent samples during the quarter(s) which previously resulted in the highest analytical result.
(e) All public water systems (community; non-tran sient, non-community; and transient, non-community systems) shall monitor to determine compliance with the maximum contaminant level for nitrite in §141.62(b).
(1) All public water systems shall take one sample at each sampling point in the compliance period beginning January 1, 1993 and ending December 31, 1995.
(2) After the initial sample, systems where an analytica l result for nitrite is <50 percent of the MCL shall monitor at the frequency specified by the State.

(3) For community, non-transient, non-community, and transient non-community water systems, the repeat monitoring frequency for any water system shall be quarterly for at least one year following any one sample in which the concentration is ≥ 50 percent of the MCL. The State may allow a system to reduce the sampling frequency to annually after determining the system is reliably and consistently less than the MCL.

(4) Systems which are monitoring annually shall take each subsequent sample during the quarter(s) which previously resulted in the highest analytical result.
(f) Confirmation samples: 

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...(1) Where the results of sampling for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium or thallium indicate an exceedance of the maximum contaminant level, the State may require that one additional sample be collected as soon as possible after the initial sample was taken (but not to exceed two weeks) at the same sampling point.

(2) Where nitrate or nitrite sampling results in dicate an exceedance of the maximum contaminant level, the system shall take a confirmation sample within 24 hours of the system's receipt of notification of the analytical results of the first sample. Systems unabl e to comply with the 24-hour sampling requirement must immediately notify persons se rved by the public water system in accordance with §141.202 and meet other Tier 1 public notification requirements under Subpart Q of this part. Systems exercising this option must take and analyze a confirmation sample within two weeks of notifi cation of the analytical results of the first sample.
(3) If a State-required confirmation sample is taken for any contaminant, then the results of the initial and confirmation sample shall be averaged. The result ing average shall be used to determine the system's compliance in accordance with paragraph (i) of this section. States have the discretion to delete results of obvious sampling errors.

(g) The State may require more frequent monitoring than specified in paragraphs (b), (c), (d) and (e) of this section or may require confirmation samples for positive and negative results at its discretion.
(h) Systems may apply to the State to conduct more frequent monitoring than the minimum monitoring frequencies specified in this section.
(i) Compliance with §§141.11 or 141.62(b) (as approp riate) shall be determined based on the analytical result(s) obtained at each sampling point.
(1) For systems which are conducting monitoring at a frequency greater than annual, compliance with the maximum contaminant levels for antimony, ar senic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium or thallium is determined by a running annual average at any sampling point. If the average at any sampling point is greater than the MCL, then the system is out of compliance. If any one sample woul d cause the annual average to be exceeded, then the system is out of compliance immediately. Any sample below the method detection limit shall be calculated at zero for the purpose of determining the annual average. If a system fails to collect the required number of samples, compliance (average concentration) will be based on the total number of samples collected.
(2) For systems which are monitoring annually, or less frequently, the system is out of compliance with the maximum contaminant levels for antimony, ar senic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium or thallium if the level of a contaminant is greater than the MCL. If confirmation samples are required by the State, the determination of compliance will be based on the annual average of the initial MCL exceedance and any State-required confirmation samples. If a system fails to collect the required numberof samples, compliance (average concentration) will be based on the total number of samples collected.
(3) Compliance with the maximum contaminant levels for nitrate and nitrate is determined based on one sample if the levels of these contaminants are belowthe MCLs. If the levels of nitrate and/or nitrite exceed the MCLs in the initial sample, a confirmati on sample is required in accordance with paragraph (f)(2) of this section, and compliance shall be determined based on the average of the initial and confirmation samples.
(4) Arsenic sampling results will be reported to the nearest 0.001 mg/L.
(j) Each public water system shall monitor at the time designated by the State during each compliance period.
(k) Inorganic analysis:

(1) Analysis for the following contaminants shall be conducted in accordance with the methods in the following table, or the alternative methods listed in appendix A to subpart C of this part, or their equivalent as determined by EPA. Cr iteria for analyzing arsenic, barium, beryllium, cadmium, calcium, chromium, copper, lead, nickel, selenium, sodium, and thallium with digestion or directly without digestion, and other analytical test procedures are contained in Technical Notes on Drinking Water Methods, EPA–600/R–94–173, October 1994. This document is available from the National Service Center for Environmental Publications (NSCEP), P.O. Box 42419, Cincinnati, OH 45242–0419 or http://www.epa.gov/nscep/

.



## Contaminant Methodology 13 

## EPA ASTM 3 

## SM 4 

## (18th, 19th ed.) SM 4 

## (20th ed.) SM Online 22 

## Other 1. Alkalinity Titrimetric D1067–92, 02 B 2320 B 2320 B 2320 B– 97 Electrometric titration I–1030– 85 5 

## 2. Antimony Inductively Coupled Plasma (ICP)— Mass Spectrometry 200.8 2



## Hydride-Atomic Absorption D3697–92, 02 Atomic Absorption; Platform 200.9 2


## Atomic Absorption; Furnace 3113 B 3113 B– 99 3. Arsenic 14 

## ICP-Mass Spectrometry 200.8 2


## Atomic Absorption; 200.9 2 

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## Platform Atomic Absorption; Furnace D2972–97, 03 C 3113 B 3113 B– 99 Hydride Atomic Absorption D1972–97, 03 B 3114 B 3114 B– 97 4. Asbestos Transmission Electron Microscopy 100.1 9



## Transmission Electron Microscopy 100.2 10



## 5. Barium Inductively Coupled Plasma 200.7 2 

## 3120 B 3120 B 3120 B– 99 ICP-Mass Spectrometry 200.8 2


## Atomic Absorption; Direct 3111D 3111 D– 99 Atomic Absorption; Furnace 3113 B 3113 B– 99 6. Beryllium Inductively Coupled Plasma 200.7 2 

## 3120 B 3120 B 3120 B– 99 ICP-Mass Spectrometry 200.8 2


## Atomic Absorption; Platform 200.9 2


## Atomic Absorption; Furnace D3645–97, 03 B 3113 B 3113 B– 99 7. Cadmium Inductively Coupled Plasma 200.7 2



## ICP-Mass Spectrometry 200.8 2


## Atomic Absorption; Platform 200.9 2


## Atomic Absorption; Furnace 3113 B 3113 B– 99 8. Calcium EDTA titrimetric D511–93, 03 A 3500– Ca D 3500– Ca B 3500– Ca B–97 Atomic Absorption; Direct Aspiration D511–93, 03 B 3111 B 3111 B– 99 Inductively Coupled Plasma 200.7 2 

## 3120 B 3120 B 3120 B– 99 Ion Chromatography D6919–03
9. Chromium Inductively Coupled Plasma 200.7 2 

## 3120 B 3120 B 3120 B– 99 ICP-Mass Spectrometry 200.8 2


## Atomic Absorption; Platform 200.9 2


## Atomic Absorption; Furnace 3113 B 3113 B– 99 10. Copper Atomic Absorption; Furnace D1688–95, 02 C 3113 B 3113 B– 99 Atomic Absorption; Direct Aspiration D1688–95, 02 A 3111 B 3111 B– 99 Inductively Coupled Plasma 200.7 2 

## 3120 B 3120 B 3120 B– 99 ICP-Mass spectrometry 200.8 2


## Atomic Absorption; Platform 200.9 2



## 11. Conductivity Conductance D1125–95 (Reapproved 1999) A 2510 B 2510 B 2510 B– 97
12. Cyanide Manual Distillation followed by D2036–98 A 4500– CN − 

## C 4500– CN − 

## C Spectrophotometric, Amenable D2036–98 B 4500– CN − 

## G 4500– CN − 

## G 4500– CN − 

## G– 99 

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...

## Spectrophotometric Manual D2036–98 A 4500– CN − 

## E 4500– CN − 

## E 4500– CN − 

## E– 99 I–3300– 85 5



## Spectrophotometric Semiautomated 335.4 6



## Selective Electrode 4500– CN − 

## F 4500– CN − 

## F 4500– CN − 

## F– 99 UV, Distillation, Spectrophotometric Kelada– 01 17 

## Micro Distillation, Flow Injection, Spectrophotometric QuikChem 10–204– 00–1–X 18 

## Ligand Exchange and Amperometry 21 

## D6888–04 OIA– 1677, DW 20 

## 13. Fluoride Ion Chromatography 300.0 6



## , 300.1 19 

## D4327–97, 03 4110 B 4110 B 4110 B– 00 Manual Distill.; Color. SPADNS 4500– F − 

## B, D 4500– F − 

## B, D 4500– F − 

## B, D– 97 Manual Electrode D1179–93, 99 B 4500– F − 

## C 4500– F − 

## C 4500– F − 

## C–97 Automated Electrode 380– 75WE 11 

## Automated Alizarin 4500– F − 

## E 4500– F − 

## E 4500– F − 

## E–97 129– 71W 11 

## Capillary Ion Electrophoresis D6508, Rev. 2 23 

## 14. Lead Atomic Absorption; Furnace D3559–96, 03 D 3113 B 3113 B– 99 ICP–Mass spectrometry 200.8 2


## Atomic Absorption; Platform 200.9 2



## Differential Pulse Anodic Stripping Voltametry Method 1001 16



## 15. Magnesium Atomic Absorption D511–93, 03 B 3111 B 3111 B– 99 ICP 200.7 2 

## 3120 B 3120 B 3120 B– 99 Complexation Titrimetric Methods D511–93, 03 A 3500– Mg E 3500– Mg B 3500– Mg B–97 Ion Chromatography D6919–03
16. Mercury Manual, Cold Vapor 245.1 2 

## D3223–97, 02 3112 B 3112 B– 99 Automated, Cold Vapor 245.2 1



## ICP–Mass Spectrometry 200.8 2


## 17. Nickel Inductively Coupled Plasma 200.7 2 

## 3120 B 3120 B 3120 B– 99 ICP–Mass Spectrometry 200.8 2


## Atomic Absorption; Platform 200.9 2


## Atomic Absorption; Direct 3111 B 3111 B– 99 Atomic Absorption; Furnace 3113 B 3113 B– 99 18. Nitrate Ion Chromatography 300.0 6 

## 300.1 19 

## D4327–97, 03 4110 B 4110 B 4110 B– 00 B–1011 8



## Automated Cadmium Reduction 353.2 6 

## D3867–90 A 4500– NO3 − 

## F 4500– NO3 − 

## F 4500– NO3 − 

## F– 00 

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...

## Ion Selective Electrode 4500– NO3 − 

## D 4500– NO3 − 

## D 4500– NO3 − 

## D– 00 601 7



## Manual Cadmium Reduction D3867–90 B 4500– NO3 − 

## E 4500– NO3 − 

## E 4500– NO3 − 

## E– 00 Capillary Ion Electrophoresis D6508, Rev. 2 23 

## 19. Nitrite Ion Chromatography 300.0 6 

## 300.1 19 

## D4327–97, 03 4110 B 4110 B 4110 B– 00 B–1011 8



## Automated Cadmium Reduction 353.2 6 

## D3867–90 A 4500– NO3 − 

## F 4500– NO3 − 

## F 4500– NO3 − 

## F– 00 Manual Cadmium Reduction D3867–90 B 4500– NO3 − 

## E 4500– NO3 − 

## E 4500– NO3 − 

## E– 00 Spectrophotometric 4500– NO2 − 

## B 4500– NO2 − 

## B 4500– NO2 − 

## B– 00 Capillary Ion Electrophoresis D6508, Rev. 2 23

## 20. Orthophosphate 12 

## Colorimetric, Automated, Ascorbic Acid 365.1 6 

## 4500– P F 4500– P F
Colorimetric, ascorbic acid, single reagent D515–88 A 4500– P E 4500– P E

Colorimetric Phosphomolybdate; I–1601– 85 5

## Automatedsegmented flow; I–2601– 90 5 

## Automated Discrete I–2598– 85 5 

## Ion Chromatography 300.0 6 

## 300.1 19 

## D4327–97, 03 4110 B 4110 B 4110 B– 00 Capillary Ion Electrophoresis D6508, Rev. 2 23 

## 21. pH Electrometric 150.1, 150.2 1 

## D1293–95, 99 4500– H + 

## B 4500– H + 

## B 4500– H + 

## B–00 22. Selenium Hydride-Atomic Absorption D3859–98, 03 A 3114 B 3114 B– 97 ICP–Mass Spectrometry 200.8 2


## Atomic Absorption; Platform 200.9 2


## Atomic Absorption; Furnace D3859–98, 03 B 3113 B 3113 B– 99 23. Silica Colorimetric, Molybdate Blue I–1700– 85 5

## Automatedsegmented Flow I–2700– 85 5 

## Colorimetric D859–94, 00 Molybdosilicate 4500– Si D 4500– SiO2 C 4500– SiO2 C– 97 Heteropoly blue 4500– Si E 4500– SiO2 D 4500– SiO2 D– 97 Automated for Molybdate-reactive Silica 4500– Si F 4500– SiO2 E 4500– SiO2 E– 97 Inductively Coupled Plasma 200.7 2 

## 3120 B 3120 B 3120 B– 99 24. Sodium Inductively Coupled Plasma 200.7 2


## Atomic Absorption; Direct Aspiration 3111 B 3111 B– 99 

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...The procedures shall be done in accordance with the documents listed below. The incorporation by reference of the following documents listed in footnotes 1–11, 16–20, and 22–23 was approved by the Director of the Federal R egister in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the documents may be obtained from the sources li sted below. Information regarding obtaining these documents can be obtained from the Safe Drinking Water Hotline at 800–426–4791. Documents may be inspected at EPA's Drinking Water Docket, EPA We st, 1301 Constitution Avenue, NW., Room 3334, Washington, DC 20460 (Telephone: 202–566–2426); or at the National Archives and Records A dministration (NARA). For information on the availab ility of this material at NARA, call 202–741–6030, or go to: http://www.archives.gov/federal_register/code_o f_federal_regulations/ibr_locations.html

.

1 “Methods for Chemical Analysis of Water and Wastes,” EPA/600/4–79/020, March 1983. Available at NTIS, PB84–128677.

2 “Methods for the Determination of Metals in Environmental Samples—Supplement I,” EPA/600/R– 94/111, May 1994. Available at NTIS, PB95–125472.

3 Annual Book of ASTM Standards, 1994, 1996, 1999, or 2003, Vols. 11.01 and 11.02, ASTM International; any year containing the cited version of the method may be used. The previous versions of D1688–95A, D1688–95C (copper), D3559–95D (lead), D1293–95 (pH), D1125–91A (conductivity) and D859–94 (silica) are also approved. These previ ous versions D1688–90A, C; D3559–90D, D1293–84, D1125–91A and D859–88, respectively are located in the Annual Book of ASTM Standards, 1994, Vol. 11.01. Copies may be obtained from ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428.

4 Standard Methods for the Examination of Water and Wastewater, 18th edition (1992), 19th edition (1995), or 20th edition (1998). American PublicHealth Association, 1015 Fifteenth Street, NW., Washington, DC 20005. The cited methods published in any of these three editions may be used, except that the versions of 3111 B, 3111 D, 3113 B and 3114 B in the 20th edition may not be used.

5 Method I–2601–90, Methods for Analysis by the U.S. Geological Survey Na tional Water Quality Laboratory—Determination of Inorganic and Organic Constituents in Water and Fluvial Sediment, Open File Report 93–125, 1993; For Methods I–1030–85; I–1601–85; I–1700–85; I–2598–85; I–2700–85; and I–3300–85 See Techniques of Water Resources Investigation of the U.S. Geological Survey, Book 5, Chapter A–1, 3rd edition., 1989; Available from Infor mation Services, U.S. Geological Survey, Federal Center, Box 25286, Denver, CO 80225–0425.

6 “Methods for the Determination of Inorganic Substances in Environmental Samples,” EPA/600/R– 93/100, August 1993. Available at NTIS, PB94–120821.

7 The procedure shall be done in accordance with the Technical Bulletin 601 ” Standard Method of Test for Nitrate in Drinking Water,” July 1994, PN 221890 –001, Analytical Technology, Inc. Copies may be obtained from ATI Orion, 529 Main Street, Boston, MA 02129.

8 Method B–1011, “Waters Test Method for Determination of Nitrite/Nitrate in Water Using Single Column Ion Chromatography,” August 1987. Copies may be obtained from Waters Corporation, Technical Services Division, 34 Maple Street, Milford, MA 01757, Telephone: 508/482–2131, Fax: 508/482–3625.

9 Method 100.1, “Analytical Method For Determination of Asbestos Fibers in Water,” EPA/600/4–83/043, EPA, September 1983. Available at NTIS, PB83–260471.

10 Method 100.2, “Determination of As bestos Structure Over 10- μ m In Length In Drinking Water,” EPA/600/R–94/134, June 1994. Available at NTIS, PB94–201902.

11 Industrial Method No. 129–71W, “Fluoride in Water and Wastewater,” December 1972, and Method No. 380–75WE, “Fluoride in Water and Wastewater,” February 1976, Technicon Industrial Systems. Copies may be obtained from Bran & Luebbe, 1025 Busch Parkway, Buffalo Grove, IL 60089.

12 Unfiltered, no digestion or hydrolysis.

13 Because MDLs reported in EPA Methods 20 0.7 and 200.9 were determined using a 2x preconcentration step during sample digestion, MDLs determined when samples are analyzed by direct analysis ( i.e. , no sample digestion) will be higher. For direct analysis of cadmium by Method 200.7, sample preconcentration using pneumatic nebulizatio n may be required to achieve lower detection limits. Preconcentration may also be required for direct analysis of antimony, lead, and thallium by Method 200.9; antimony and lead by Method 3113 B; and lead by Method D3559–90D, unless multiple in-furnace depositions are made.

14 If ultrasonic nebulization is used in the determinati on of arsenic by Method 200.8, the arsenic must be in the pentavalent state to provide un iform signal response. For direct analysis of arsenic with Method 200.8 using ultrasonic nebulization, samples and standards must contain 1 mg/L of sodium hypochlorite.

15 [Reserved]

16 The description for Method Number 1001 for lead is available from Palintest, LTD, 21 Kenton Lands Road, P.O. Box 18395, Erlanger, KY 41018. Or from the Hach Company, P.O. Box 389, Loveland, CO 80539.

17 The description for the Kelada-01 Method, “Kelada Au tomated Test Methods for Total Cyanide, Acid Dissociable Cyanide, And Thiocyanate,” Revision 1.2, August 2001, EPA # 821–B–01–009 for cyanide 

## Ion Chromatography D6919–03

25. Temperature Thermometric 2550 2550 2550–00

26. Thallium ICP–Mass Spectrometry 200.8 2


## Atomic Absorption; Platform 200.9 2 

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...is available from the National Technical Information Service (NTIS), PB 2001–108275, 5285 Port Royal Road, Springfield, VA 22161. The toll free telephone number is 800–553–6847. Note: A 450–W UV lamp may be used in this method instead of the 550–W lamp specified if it provides performance within the quality control (QC) acceptance criteria of the method in a given instrument. Similarly, modified flow cell configurations and flow conditions may be used in the method, provided that the QC acceptance criteria are met.

18 The description for the QuikChem Method 10–204–00–1–X, “Digestion and disti llation of total cyanide in drinking and wastewaters using MICRO DIST and d etermination of cyanide by flow injection analysis,” Revision 2.1, November 30, 2000, for cyanide is av ailable from Lachat Instruments, 6645 W. Mill Rd., Milwaukee, WI 53218. Telephone: 414–358–4200.

19 “Methods for the Determination of Organic and Inorganic Compounds in Drinking Water,” Vol. 1, EPA 815–R–00–014, August 2000. Available at NTIS, PB2000–106981.

20 Method OIA–1677, DW “Available Cyanide by Flow Injection, Ligand Exchange, and Amperometry,” January 2004. EPA–821–R–04–001, Available from ALPKEM, A Division of OI Analytical, P.O. Box 9010, College Station, TX 77842–9010.

21 Sulfide levels below those detected using lead acetate paper may produce positive method interferences. Test samples using a more sensitiv e sulfide method to determine if a sulfide interference is present, and treat samples accordingly.

22 Standard Methods Online are available at http://www.standardmethods.org. The year in which each method was approved by the Standard Methods Commi ttee is designated by the last two digits in the method number. The methods listed are the only online versions that may be used.

23 Method D6508, Rev. 2, “Test Method for Determinati on of Dissolved Inorganic Anions in Aqueous Matrices Using Capillary Ion Electrophoresis and Chromate Electrolyte,” available from Waters Corp, 34 Maple St, Milford, MA, 01757, Telephone: 508/482–2131, Fax: 508/482–3625.

(2) Sample collection for antimony, arsenic, asbest os, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, nitrate, ni trite, selenium, and thallium under this section shall be conducted using the sample preservation, container, and maximu m holding time procedures specified in the table below:

1 For cyanide determinations samples must be adjus ted with sodium hydroxide to pH 12 at the time off collection. When chilling is indicated the sample mustbe shipped and stored at 4 °C or less. Acidification of nitrate or metals samples may be with a concentrated acid or a dilute (50% by volume) solution of the applicable concentrated acid. Acidification of samples for metals analysis is encouraged and allowed at the laboratory rather than at the time of sampling provided the shipping time and other instructions in Section 8.3 of EPA Methods 200.7 or 200.8 or 200.9 are followed.

2 P=plastic, hard or soft; G=glass, hard or soft.

3 In all cases samples should be analyzed as soon after collection as possible. Fo llow additional (if any) information on preservation, containers or hol ding times that is specified in method.

4 Instructions for containers, preservation procedures and holding times as specified in Method 100.2 must be adhered to for all compliance analysesincluding those conducted with Method 100.1.

5 If the sample is chlorinated, the holding time for an unacidified sample kept at 4 °C is extended to 14 days.

6 Nitrate-Nitrite refers to a measurement of total nitrate.

(3) Analysis under this section shall only be cond ucted by laboratories that have been certified by EPA or the State. Laboratories may conduct sample anal ysis under provisional certification until January 1, 1996. To receive certification to conduct analyses for antimony, arsenic, asbes tos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, ni ckel, nitrate, nitrite and selenium and thallium, the laboratory must: 

## Contaminant Preservative 1 

## Container2 

## Time 3 

## Antimony HNO 3 

## P or G 6 months Arsenic Conc HNO 3 

## to pH <2 P or G 6 months Asbestos 4 °C P or G 48 hours 4 

## Barium HNO 3 

## P or G 6 months Beryllium HNO 3 

## P or G 6 months Cadmium HNO 3 

## P or G 6 months Chromium HNO 3 

## P or G 6 months Cyanide 4 °C, NaOH P or G 14 days Fluoride None P or G 1 month Mercury HNO 3 

## P or G 28 days Nickel HNO 3 

## P or G 6 months Nitrate 4 °C P or G 48 hours 5


## Nitrate-Nitrite 6 

## H 2 

## SO 4 

## P or G 28 days Nitrite 4°C P or G 48 hours Selenium HNO 3 

## P or G 6 months Thallium HNO 3 

## P or G 6 months 

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...(i) Analyze Performance Evaluation (PE) samples provided by EPA, the State or by a third party (with the approval of the State or EPA) at least once a year.

(ii) For each contaminant that has been included in the PE sample and for each method for which the laboratory desires certification achieve quantitative results on the analyses that are within the following acceptance limits:

(l) Analyses for the purpose of determining comp liance with §141.11 shall be conducted using the requirements specified in paragrap hs (l) through (q) of this section.
(1) Analyses for all community water systems utilizing surface water sources shall be completed by June 24, 1978. These analyses shall be repeated at yearly intervals.
(2) Analyses for all community water systems utilizing only ground water sources shall be completed by June 24, 1979. These analyses shall be repeated at three-year intervals.
(3) For non-community water systems, whether suppli ed by surface or ground sources, analyses for nitrate shall be completed by December 24, 1980. These analyses shall be repeated at intervals determined by the State.
(4) The State has the authority to determine compliance or initiate enforcement action based upon analytical results and other information compiled by their sanctioned representatives and agencies.
(m) If the result of an analysis made under paragraph (l ) of this section indicates that the level of any contaminant listed in §141.11 exceeds the maximum co ntaminant level, the supplier of the water shall report to the State within 7 days and initiate three addi tional analyses at the same sampling point within one month.
(n) When the average of four analyses made pursuant to paragraph (m) of this section, rounded to the same number of significant figures as the maximum contaminant level for the substance in question, exceeds the maximum contaminant level, the supplier of water shall notify the State pursuant to §141.31 and give notice to the public pursuant to subpart Q. M onitoring after public noti fication shall be at a frequency designated by the State and shall continue u ntil the maximum contaminant level has not been exceeded in two successive samples or until a monitoring schedule as a condition to a variance, exemption or enforcement action shall become effective.
(o) The provisions of paragraphs (m) and (n) of this section notwithstanding, compliance with the maximum contaminant level for nitrate shall be determined on the basis of the mean of two analyses. When a level exceeding the maximum contaminant level for nitrate is found, a second analysis shall be initiated within 24 hours, and if the mean of the two analyses exceeds the maximum contaminant level, the supplier of water shall report his findings to th e State pursuant to §141.31 and shall notify the public pursuant to subpart Q.
(p) For the initial analyses required by paragraph (l) (1), (2) or (3) of this section, data for surface waters acquired within one year prior to the effective date and data for ground waters acquired within 3 years prior to the effective date of this part may be substituted at the discretion of the State.
(q) [Reserved]

[56 FR 3579, Jan. 30, 1991]

Editorial Note: For Federal Register citations affecting §141.23, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.fdsys.gov.


### § 141.24 Organic chemicals, sampling and analytical requirements.

top
(a)–(d) [Reserved]
(e) Analyses for the contaminants in this section sh all be conducted using the methods listed in the following table, or the alternative methods listed in appendix A to subpart C of this part, or their equivalent as determined by EPA.
(1) The following documents are incorporated by reference. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be inspected at EPA's Drinking Wate r Docket, 1301 Constitution Avenue, NW., EPA West,



## Contaminant Acceptance limit Antimony ±30 at ≥ 0.006 mg/1 Arsenic ±30 at ≥ 0.003 mg/L Asbestos 2 standard deviations based on study statistics. Barium ±15% at ≥ 0.15 mg/1 Beryllium ±15% at ≥ 0.001 mg/1 Cadmium ±20% at ≥ 0.002 mg/1 Chromium ±15% at ≥ 0.01 mg/1 Cyanide ±25% at ≥ 0.1 mg/1 Fluoride ±10% at ≥ 1 to 10 mg/1 Mercury ±30% at ≥ 0.0005 mg/1 Nickel ±15% at ≥ 0.01 mg/1 Nitrate ±10% at ≥ 0.4 mg/1 Nitrite ±15% at ≥ 0.4 mg/1 Selenium ±20% at ≥ 0.01 mg/1 Thallium ±30% at ≥ 0.002 mg/1 

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...Room 3334, Washington, DC 20460 (Telephone: 202 –566–2426); or at the National Archives and Records Administration (NARA). For information on the av ailability of this material at NARA, call 202– 741–6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Method 508A and 515.1 are in Methods for the Determination of Organic Compounds in Drinking Water, EPA/600/4– 88–039, December 1988, Revised, July 1991. Methods 547, 550 and 550.1 are in Methods for the Determination of Organic Compounds in Drinking Water—Supplement I, EPA/600–4–90–020, July 1990. Methods 548.1, 549.1, 552.1 and 555 are in Methods for the Determination of Organic Compounds in Drinking Water—Supplement II, EPA/600/R–92–129, August 1992. Methods 502.2, 504.1, 505, 506, 507, 508, 508.1, 515.2, 524.2 525.2, 531.1, 551.1 and 552.2 are in Methods for the Determination of Organic Compounds in Drinking Water––Supplement III, EPA/600/R–95–131, August 1995. Method 1613 is titled “Tetra-through Octa-Chlorinated Diox ins and Furans by Isotope-Dilution HRGC/HRMS,” EPA/821–B–94–005, October 1994. These documents are available from the National Technical Information Service, NTIS PB91–231480, PB91–146027, PB92–207703, PB95–261616 and PB95– 104774, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, Virginia 22161. The toll free number is: 800–553–6847. Method 6651 shall be followed in accordance with Standard Methods for the Examination of Water and Wastewater, 18th edition (1992), 19th edition (1995), or 20th edition (1998), A merican Public Health Associati on (APHA); any of these three editions may be used. Method 6610 shall be followed in accordance with Standard Methods for the Examination of Water and Wastewater, (18th Edition Supplement) (1994), or with the 19th edition (1995) or 20th edition (1998) of Standard Methods for the Examination of Water and Wastewater; any of these publications may be used. The A PHA documents are available from APHA, 1015 Fifteenth Street NW., Washington, DC 20005. Other required analytical test procedur es germane to the conduct of these analyses are contained in Technical Notes on Drinking Water Methods, EPA/600/R–94–173, October 1994, NTIS PB95–104766. EPA Methods 515.3 and 549.2 are available from U.S. Envi ronmental Protection Agency, National Exposure Research Laboratory (NERL)–Cincinnati, 26 WestMartin Luther King Drive, Cincinnati, OH 45268. A STM Method D 5317–93, 98 (Reapproved 2003) is available in the Annual Book of ASTM Standards, (1999), Vol. 11.02, ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428, any edition containing the cited version of the metho d may be used. EPA Method 515.4, “Determination of Chlorinated Acids in Drinking Water by Liquid-Liq uid Microextraction, Deriv atization and Fast Gas Chromatography with Electron Capture Detection,” Revision 1.0, April 2000, EPA/815/B–00/001 and EPA Method 552.3, “Determination of Haloacetic Acids and Dalapon in Drinking Water by Liquid-Liquid Microextraction, Derivatization, and Gas Chromatography with Electron Capture Detection,” Revision 1.0, July 2003, EPA 815–B–03–002, can be accessed and downloaded directly online at http://www.epa.gov/safewater/m ethods/sourcalt.html. Syngenta Method AG–625, “Atrazine in Drinking Water by Immunoassay,” February 2001, is availabl e from Syngenta Crop Protection, Inc., 410 Swing Road, P.O. Box 18300, Greensboro, NC 27419. Telephone: 336–632–6000. Method 531.2 “Measurement of N-methylcarbamoyloximes and N- methylcarbamates in Water by Direct Aqueous Injection HPLC with Postcolumn Derivatization ,” Revision 1.0, September 2001, EPA 815–B–01–002, can be accessed and downloaded directly online at http://www.epa.gov/safewater/m ethods/sourcalt.html.



## Contaminant EPA method Standard methods ASTM Other 1. Benzene 502.2, 524.2 2. Carbon tetrachloride 502.2, 524.2, 551.1 3. Chlorobenzene 502.2, 524.2 4. 1,2-Dichlorobenzene 502.2, 524.2 5. 1,4-Dichlorobenzene 502.2, 524.2 6. 1,2-Dichloroethane 502.2, 524.2 7. cis-Dichloroethylene 502.2, 524.2 8. trans-Dichloroethylene 502.2, 524.2 9. Dichloromethane 502.2, 524.2 10. 1,2-Dichloropropane 502.2, 524.2 11. Ethylbenzene 502.2, 524.2 12. Styrene 502.2, 524.2 13. Tetrachloroethylene 502.2, 524.2, 551.1 14. 1,1,1-Trichloroethane 502.2, 524.2, 551.1 15. Trichloroethylene 502.2, 524.2, 551.1 16. Toluene 502.2, 524.2 17. 1,2,4-Trichlorobenzene 502.2, 524.2 18. 1,1-Dichloroethylene 502.2, 

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...

## 524.2 19. 1,1,2-Trichloroethane 502.2, 524.2, 551.1 20. Vinyl chloride 502.2, 524.2 21. Xylenes (total) 502.2, 524.2 22. 2,3,7,8-TCDD (dioxin) 1613 23. 2,4–D 4 

## (as acids, salts, and esters) 515.2, 555, 515.1, 515.3, 515.4 D5317–93, 98 (Reapproved 2003)

24. 2,4,5–TP 4 

## (Silvex) 515.2, 555, 515.1, 515.3, 515.4 D5317–93, 98 (Reapproved 2003)

25. Alachlor2 

## 507, 525.2, 508.1, 505, 551.1 26. Atrazine 2 

## 507, 525.2, 508.1, 505, 551.1 Syngenta 5

## AG– 625

27. Benzo(a)pyrene 525.2, 550, 550.1 28. Carbofuran 531.1, 531.2 6610
29. Chlordane 508, 525.2, 508.1, 505 30. Dalapon 552.1 515.1, 552.2, 515.3, 515.4, 552.3 31. Di(2-ethylhexyl)adipate 506, 525.2 32. Di(2-ethylhexyl) phthalate 506, 525.2 33. Dibromochloropropane (DBCP) 504.1, 551.1 34. Dinoseb 4 

## 515.2, 555, 515.1, 515.3, 515.4 35. Diquat 549.2 36. Endothall 548.1 37. Endrin 508, 525.2, 508.1, 505, 551.1 38. Ethylene dibromide (EDB) 504.1, 551.1 39. Glyphosate 547 6651 40. Heptachlor 508, 525.2, 508.1, 505, 551.1 41. Heptachlor Epoxide 508, 525.2, 

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...1 [Reserved]

2 Substitution of the detector specified in Method 505 , 507, 508 or 508.1 for the purpose of achieving lower detection limits is allowed as follows. Either an electron capture or nitrogen phosphorous detector may be used provided all regulatory requirem ents and quality control criteria are met.

3 PCBs are qualitatively identified as Aroclors and measured for compliance purposes as decachlorobiphenyl. Users of Method 505 may have more difficulty in achiev ing the required detection limits than users of Methods 508.1, 525.2 or 508.

4 Accurate determination of the chlorinated esters requires hydrolysis of the sample as described in EPA Methods 515.1, 515.2, 515.3, 515.4 and 555 and ASTM Method D5317–93.

5 This method may not be used for the analysis of atrazi ne in any system where chlorine dioxide is used for drinking water treatment. In samples from all other systems, any result for atrazine generated by Method AG–625 that is greater than one-half the maximum contaminant level (MCL) (in other words, greater than 0.0015mg/L or 1.5 μ g/L) must be confirmed using another approved method for this contaminant and should use additional volume of the original sample collected for compliance monitoring. In instances where a result from Method AG–625 triggers such confirmatory testing, the confirmatory result is to be used to determine compliance.
(2) [Reserved] 

## 508.1, 505, 551.1 42. Hexachlorobenzene 508, 525.2, 508.1, 505, 551.1 43. Hexachlorocyclopentadiene 508, 525.2, 508.1, 505, 551.1 44. Lindane 508, 525.2, 508.1, 505, 551.1 45. Methoxychlor 508, 525.2, 508.1, 505, 551.1 46. Oxamyl 531.1, 531.2 6610

47. PCBs 3 

## (as decachlorobiphenyl) 508A

48. PCBs 3 

## (as Aroclors) 508.1, 508, 525.2, 505 49. Pentachlorophenol 515.2, 525.2, 555, 515.1, 515.3, 515.4 D5317–93, 98 (Reapproved 2003)

50. Picloram 4 

## 515.2, 555, 515.1, 515.3, 515.4 D5317–93, 98 (Reapproved 2003)

51. Simazine 2 

## 507, 525.2, 508.1, 505, 551.1 52. Toxaphene 508, 508.1, 525.2, 505 53. Total Trihalomethanes 502.2, 524.2, 551.1 

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...(f) Beginning with the initial compliance period, an alysis of the contaminants listed in §141.61(a) (1) through (21) for the purpose of determining compliance with the maximum contaminant level shall be conducted as follows:

(1) Groundwater systems shall take a minimum of one sample at every entry point to the distribution system which is representative of each well after treatment (hereafter called a sampling point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source, treatment plant, or within the distribution system.
(2) Surface water systems (or combined surface/ground) shall take a minimum of one sample at points in the distribution system that are representative of each source or at each entry point to the distribution system after treatment (hereafter called a sampling point). Each sample must be taken at the same sampling point unless conditions make another sa mpling point more representative of each source, treatment plant, or within the distribution system.
(3) If the system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry po int to the distribution system during periods of normal operating conditions ( i.e. , when water representative of all sources is being used).
(4) Each community and non-transient non-community water system shall take four consecutive quarterly samples for each contaminant listed in § 141.61(a) (2) through (21) during each compliance period, beginning in the initial compliance period.
(5) If the initial monitoring for contaminants listed in §141.61(a) (1) through (8) and the monitoring for the contaminants listed in §141.61(a) (9) through (21) as allowed in paragraph (f)(18) has been completed by December 31, 1992, and the system did not detec t any contaminant listed in §141.61(a) (1) through (21), then each ground and surface water system shall take one sample annually beginning with the initial compliance period.
(6) After a minimum of three years of annual sampling, the State may allow groundwater systems with no previous detection of any contaiminant listed in §141.61(a) to take one sample during each compliance period.
(7) Each community and non-transient non-communi ty ground water system which does not detect a contaminant listed in §141.61(a) (1) through (21) may apply to the State for a waiver from the requirements of paragraphs (f)(5) and (f)(6) of this section after completing the initial monitoring. (For purposes of this section, detection is defined as ≥ 0.0005 mg/l.) A waiver shall be effective for no more than six years (two compliance periods). States may also issue waivers to small systems for the initial round of monitoring for 1,2,4-trichlorobenzene.
(8) A State may grant a waiver after evaluating the following factor(s):

(i) Knowledge of previous use (inc luding transport, storage, or disposal) of the contaminant within the watershed or zone of influence of the s ystem. If a determination by the State reveals no previous use of the contaminant within the watershed or z one of influence, a waiver may be granted.

(ii) If previous use of the conta minant is unknown or it has been used previously , then the following factors shall be used to determine whether a waiver is granted.
(A) Previous analytical results.
(B) The proximity of the system to a potential point or non-point source of contamination. Point sources include spills and leaks of chemicals at or near a water treatment facility or at manufacturing, distribution, or storage facilities, or from haza rdous and municipal waste landfills and other waste handling or treatment facilities.
(C) The environmental persistence and transport of the contaminants.

(D) The number of persons served by the public wate r system and the proximity of a smaller system to a larger system.
(E) How well the water source is protected against co ntamination, such as whether it is a surface or groundwater system. Groundwater systems must consider factors such as depth of the well, the type of soil, and wellhead protection. Surface water systems must consider watershed protection.
(9) As a condition of the waiver a groundwater s ystem must take one sample at each sampling point during the time the waiver is effective ( i.e. , one sample during two compliance periods or six years) and update its vulnerability assessment considering the fac tors listed in paragraph (f)(8) of this section. Based on this vulnerability assessment the State must reconfirm that the system is non-vulnerable. If the State does not make this reconfirm ation within three years of the initial determination, then the waiver is invalidated and the system is required to sample annually as specified in paragraph (5) of this section.
(10) Each community and non-transient non-comm unity surface water system which does not detect a contaminant listed in §141.61(a) (1) through (21) may apply to the State for a waiver from the requirements of (f)(5) of this section after completi ng the initial monitoring. Composite samples from a maximum of five sampling points are allowed, provi ded that the detection limit of the method used for analysis is less than one-fifth of the MCL. System s meeting this criterion must be determined by the State to be non-vulnerable based on a vulnerability assessment during each compliance period. Each system receiving a waiver shall sample at th e frequency specified by the State (if any).
(11) If a contaminant listed in §141.61(a) (2) through ( 21) is detected at a level exceeding 0.0005 mg/l in any sample, then:
(i) The system must monitor quarterly at each sampling point which resulted in a detection.
(ii) The State may decrease the quarterlymonitoring requirement speci fied in paragraph (f)(11)(i) of this section provided it has determined that the system is reliably and consistently below the maximum contaminant level. In no case shall the State ma ke this determination unless a groundwater system takes a minimum of two quarterly samples and a surface water system tak es a minimum of four quarterly samples.
(iii) If the State determines that the system is reliab ly and consistently below the MCL, the State may allow the system to monitor annually. Systems which monitor annually must monitor during the quarter (s) which previously yielded the highest analytical result. 

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...(iv) Systems which have three consecutive annual samples with no detection of a contaminant may apply to the State for a waiver as specified in paragraph (f)(7) of this section.

(v) Groundwater systems which have detected one or more of the following two-carbon organic compounds: trichloroethylene, tetrachloroethylene , 1,2-dichloroethane, 1,1,1-trichloroethane, cis-1,2- dichloroethylene, trans-1,2-dichloroethylene, or 1,1- dichloroethylene shall monitor quarterly for vinylchloride. A vinyl chloride sample shall be taken at each sampling point at which one or more of the twocarbon organic compounds was detected. If the results of the first analysis do not detect vinyl chloride, the State may reduce the quarterly monitoring frequency of vinyl chloride monitoring to one sample during each compliance period. Surface water systems are required to monitor for vinyl chloride as specified by the State.

(12) Systems which violate the requirements of §141.61 (a) (1) through (21), as determined by paragraph (f)(15) of this section, must monitor quarterly. After a minimum of four consecutive quarterly samples which show the system is in compliance as specifie d in paragraph (f)(15) of this section the system and the State determines that the system is reliably and consistently below the maximum contaminant level, the system may monitor at the frequency and times specified in paragraph (f)(11)(iii) of this section.

(13) The State may require a confirmation sample for positive or negative results. If a confirmation sample is required by the State, the result must be averaged with the first sampling result and the average is used for the compliance determination as specified by paragraph (f)(15). States have discretion to delete results of obvious sampling errors from this calculation.

(14) The State may reduce the total number of samples a system must analyze by allowing the use of compositing. Composite samples from a maximum of five sampling points are allowed, provided that the detection limit of the method used for analysis is le ss than one-fifth of the MCL. Compositing of samples must be done in the laboratory and analyzed within 14 days of sample collection.

(i) If the concentration in the composite sample is greater than or equal to 0.0005 mg/l for any contaminant listed in §141.61(a), then a follow-up sample must be taken within 14 days at each sampling point included in the composite, and be analyzed for that contaminant.
(ii) If duplicates of the original sa mple taken from each sampling point used in the composite sample are available, the system may use these instead of resampling. The duplicates must be analyzed and the results reported to the State within 14 days after comp leting analysis of the composite sample, provided the holding time of the sample is not exceeded.
(iii) If the population served by the system is > 3,300 persons, then compositing may only be permitted by the State at sampling points withi n a single system. In systems serving ≤ 3,300 persons, the State may permit compositing among different systems provided the 5-sample limit is maintained.
(iv) Compositing samples prior to GC analysis.

(A) Add 5 ml or equal larger amounts of each sample (up to 5 samples are allowed) to a 25 ml glass syringe. Special precautions must be made to maintain zero headspace in the syringe.
(B) The samples must be cooled at 4 °C during this step to minimize volatilization losses.
(C) Mix well and draw out a 5-ml aliquot for analysis.
(D) Follow sample introduction, purging, an d desorption steps described in the method.
(E) If less than five samples are used for compositing, a proportionately small syringe may be used.
(v) Compositing samples prior to GC/MS analysis.
(A) Inject 5-ml or equal larger amounts of each aq ueous sample (up to 5 samples are allowed) into a 25- ml purging device using the sample intro duction technique described in the method.
(B) The total volume of the sample in the purging device must be 25 ml.
(C) Purge and desorb as described in the method.
(15) Compliance with §141.61(a) (1) through (21) shall be determined based on the analytical results obtained at each sampling point. If one sampling point is in violation of an MCL, the system is in violation of the MCL.
(i) For systems monitoring more than once per y ear, compliance with the MCL is determined by a running annual average at each sampling point.
(ii) Systems monitoring annually or less frequentlywhose sample result exceeds the MCL must begin quarterly sampling. The system will not be considered in violation of the MCL until it has completed one year of quarterly sampling.

(iii) If any sample result will cause the running annual average to exceed the MCL at any sampling point, the system is out of compliance with the MCL immediately.
(iv) If a system fails to collect the required number of samples, compliance will be based on the total number of samples collected.
(v) If a sample result is less than the detection limit, zero will be used to calculate the annual average.

(16) [Reserved]
(17) Analysis under this section shall only be conduc ted by laboratories that are certified by EPA or the State according to the following conditions (laboratori es may conduct sample an alysis under provisional certification until January 1, 1996):
(i) To receive certification to conduct analyses for the contaminants in §141.61(a) (2) through (21) the laboratory must:
(A) Analyze Performance Evaluation (PE) samples provided by EPA, the State, or by a third party (with 

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...the approval of the State or EPA) at least once a year by each method for which the laboratory desires certification.

(B) Achieve the quantitative acceptance limits under paragraphs (f)(17)(i)(C ) and (D) of this section for at least 80 percent of the regulated organic contaminants included in the PE sample.
(C) Achieve quantitative results on the analyses performed under paragraph (f)(17)(i)(A) of this section that are within ±20% of the actual amount of the su bstances in the Performance Evaluation sample when the actual amount is greater than or equal to 0.010 mg/l.
(D) Achieve quantitative results on the analyses performed under paragraph (f)(17)(i)(A) of this section that are within ±40 percent of the actual amount of the substances in the Pe rformance Evaluation sample when the actual amount is less than 0.010 mg/l.
(E) Achieve a method detection limit of 0.0005 mg/l, according to the procedures in appendix B of part 136.
(ii) To receive certification to conduct anal yses for vinyl chloride, the laboratory must:
(A) Analyze Performance Evaluation (PE) samples provided by EPA, the State, or by a third party (with the approval of the State or EPA) at least once a year by each method for which the laboratory desires certification.
(B) Achieve quantitative results on the analyses performed under paragraph (f)(17)(ii)(A) of this section that are within ±40 percent of the actual amount of viny l chloride in the Performance Evaluation sample.
(C) Achieve a method detection limit of 0.0005 mg/l, according to the procedures in appendix B of part 136.
(D) Obtain certification for the contamina nts listed in §141.61(a)(2) through (21).
(18) States may allow the use of monitoring data co llected after January 1, 1988, required under section 1445 of the Act for purposes of initial monitoring compliance. If the data are generally consistent with the other requirements of this section, the State may use these data ( i.e. , a single sample rather than four quarterly samples) to satisfy the initial monitoring requirement of paragraph (f)(4) of this section. Systems which use grandfathered samples and did not detect any contaminant listed §141.61(a)(2) through (21) shall begin monitoring annually in ac cordance with paragraph (f)(5) of this section beginning with the initial compliance period.
(19) States may increase required monitoring where necessary to detect variations within the system.
(20) Each certified laboratory must determine the method detection limit (MDL), as defined in appendix B to part 136, at which it is capable of detecting VOCs. The acceptable MDL is 0.0005 mg/l. This concentration is the detection concentration for purposes of this section.
(21) Each public water system shall monitor at the time designated by the State within each compliance period.
(22) All new systems or systems that use a new source of water that begin operation after January 22, 2004 must demonstrate compliance with the MCL within a period of time specified by the State. The system must also comply with the initial sampling fr equencies specified by the State to ensure a system can demonstrate compliance with the MCL. Routine and increased monitoring frequencies shall be conducted in accordance with the requirements in this section.
(g) [Reserved]

(h) Analysis of the contaminants listed in §141.61(c) for the purposes of determining compliance with the maximum contaminant level shall be conducted as follow s, with the exception that no monitoring is required for aldicarb, aldicarb sulfoxide or aldicarb sulfone:
(1) Groundwater systems shall take a minimum of one sample at every entry point to the distribution system which is representative of each well after treatment (hereafter called a sampling point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.
(2) Surface water systems shall take a minimum of one sample at points in the distribution system that are representative of each source or at each entry point to the distribution system after treatment (hereafter called a sampling point). Each sample must be taken at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.


### Note: For purposes of this paragraph, surface water systems include systems with a combination of surface and ground sources.

(3) If the system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry po int to the distribution system during periods of normal operating conditions ( i.e. , when water representative of all sources is being used).

(4) Monitoring frequency: (i) Each community and non-transient non-community water system shall take four consecutive quarterly samples for each contam inant listed in §141.61(c) during each compliance period beginning with the initial compliance period.
(ii) Systems serving more than 3,300 persons which do not detect a contaminant in the initial compliance period may reduce the sampling frequency to a minimum of two quarterly samples in one year during each repeat compliance period.
(iii) Systems serving less than or equal to 3,300 pers ons which do not detect a contaminant in the initial compliance period may reduce the sampling frequency to a minimum of one sample during each repeat compliance period.
(5) Each community and non-transient water system may apply to the State for a waiver from the requirement of paragraph (h)(4) of this section. A system must reapply for a waiver for each compliance period. 

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...(6) A State may grant a waiver after evaluating the following factor(s): Knowledge of previous use (including transport, storage, or di sposal) of the contaminant within the w atershed or zone of influence of the system. If a determination by the State reveals no previous use of the contaminant within the watershed or zone of influence, a waiver may be gran ted. If previous use of the contaminant is unknown or it has been used previously, then the following fac tors shall be used to determine whether a waiver is granted.
(i) Previous analytical results.

(ii) The proximity of the system to a potential point or non-point source of contamination. Point sources include spills and leaks of chemicals at or near a water treatment facility or at manufacturing, distribution, or storage facilities, or from haza rdous and municipal waste landfills and other waste handling or treatment facilities. Non-point sources in clude the use of pesticides to control insect and weed pests on agricultural areas, forest lands, home and gardens, and other land application uses.
(iii) The environmental persistence and transport of the pesticide or PCBs.
(iv) How well the water source is protected against contamination due to such factors as depth of the well and the type of soil and the integrity of the well casing.
(v) Elevated nitrate levels at the water supply source.
(vi) Use of PCBs in equipment used in the production, storage, or distribution of water ( i.e. , PCBs used in pumps, transformers, etc.).
(7) If an organic contaminant listed in §141.61(c) is detected (as defined by paragraph (h)(18) of this section) in any sample, then:
(i) Each system must monitor quarterly at ea ch sampling point which resulted in a detection.
(ii) The State may decrease the quarter ly monitoring requirement specif ied in paragraph (h)(7)(i) of this section provided it has determined that the system is reliably and consistently below the maximum contaminant level. In no case shall the State ma ke this determination unless a groundwater system takes a minimum of two quarterly samples and a surface water system tak es a minimum of four quarterly samples.
(iii) After the State determines th e system is reliably and consistently below the maximum contaminant level the State may allow the system to monitor annua lly. Systems which monitor annually must monitor during the quarter that previously yi elded the highest analytical result.
(iv) Systems which have 3 consec utive annual samples with no detection of a contaminant may apply to the State for a waiver as specified in paragraph (h)(6) of this section.
(v) If the monitoring results in detection of one or more of certain related contaminants (heptachlor and heptachlor epoxide), then subs equent monitoring shall analyze for all related contaminants.
(8) Systems which violate the requirements of §1 41.61(c) as determined by paragraph (h)(11) of this section must monitor quarterly. After a minimum of four quarterly samples show the system is in compliance and the State determines the system is reliably and consistently below the MCL, as specified in paragraph (h)(11) of this section, the system shall monitor at the frequency specified in paragraph (h)(7)(iii) of this section.
(9) The State may require a confirmation sample for positive or negative results. If a confirmation sample is required by the State, the result must be average d with the first sampling result and the average used for the compliance determination as specified by paragraph (h)(11 ) of this section. States have discretion to delete results of obvious sampling errors from this calculation.
(10) The State may reduce the total number of samples a system must analyze by allowing the use of compositing. Composite samples from a maximum of five sampling points are allowed, provided that the detection limit of the method used for analysis is le ss than one-fifth of the MCL. Compositing of samples must be done in the laboratory and analyzed within 14 days of sample collection.
(i) If the concentration in the composite sample detec ts one or more contaminants listed in §141.61(c), then a follow-up sample must be taken within 14 days at each sampling point included in the composite, and be analyzed for that contaminant.

(ii) If duplicates of the original sa mple taken from each sampling point used in the composite sample are available, the system may use these instead of resampling. The duplicates must be analyzed and the results reported to the State within 14 days after co mpletion of the composite analysis or before the holding time for the initial sample is exceeded whichever is sooner.

(iii) If the population served by the system is >3,300 persons, then compositing may only be permitted by the State at sampling points within a single system. In systems serving ≤ 3,300 persons, the State may permit compositing among di fferent systems provided the 5-sample limit is maintained.
(11) Compliance with §141.61(c) shall be determined based on the analytical results obtained at each sampling point. If one sampling point is in violation of an MCL, the system is in violation of the MCL.
(i) For systems monitoring more than once per y ear, compliance with the MCL is determined by a running annual average at each sampling point.
(ii) Systems monitoring annually or less frequently whose sample result exceeds the regulatory detection level as defined by paragraph (h)(18) of this section must begin quarterly sampling. The system will not be considered in violation of the MCL until it has completed one year of quarterly sampling.
(iii) If any sample result will cause the running annual average to exceed the MCL at any sampling point, the system is out of compliance with the MCL immediately.

(iv) If a system fails to collect the required number of samples, compliance will be based on the total number of samples collected.
(v) If a sample result is less than the detection limit, zero will be used to calculate the annual average. 

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...(12) [Reserved]
(13) Analysis for PCBs shall be conducted as follows using the methods in paragraph (e) of this section:
(i) Each system which monitors for PCBs shall analyze each sample using either Method 508.1, 525.2, 508 or 505. Users of Method 505 may have more diffi culty in achieving the required Aroclor detection limits than users of Methods 508.1, 525.2 or 508.
(ii) If PCBs (as one of seven Aroclors) are detected (as designated in this paragraph) in any sample analyzed using Method 505 or 508, the system s hall reanalyze the sample using Method 508A to quantitate PCBs (as decachlorobiphenyl).

(iii) Compliance with the PCB MCL shall be determined based upon the quantitative results of analyses using Method 508A.
(14) If monitoring data collected after January 1, 199 0, are generally consistent with the requirements of §141.24(h), then the State may allow systems to use that data to satisfy the monitoring requirement for the initial compliance period beginning January 1, 1993.
(15) The State may increase the required monitoring frequency, where necessary, to detect variations within the system (e.g., fluctuations in concentration due to seasonal us e, changes in water source).

(16) The State has the authority to determine comp liance or initiate enforcement action based upon analytical results and other information compiled by their sanctioned representatives and agencies.
(17) Each public water system shall monitor at the time designated by the State within each compliance period.
(18) Detection as used in this paragraph shall be defined as greater than or equal to the following concentrations for each contaminant. 

## Aroclor Detection limit (mg/l) 1016 0.00008 1221 0.02 1232 0.0005 1242 0.0003 1248 0.0001 1254 0.0001 1260 0.0002

Contaminant Detection limit (mg/l) Alachlor .0002 Aldicarb .0005 Aldicarb sulfoxide .0005 Aldicarb sulfone .0008 Atrazine .0001 Benzo[a]pyrene .00002 Carbofuran .0009 Chlordane .0002 Dalapon .001 1,2–Dibromo–3–chloropropane (DBCP) .00002 Di (2-ethylhexyl) adipate .0006 Di (2-ethylhexyl) phthalate .0006 Dinoseb .0002 Diquat .0004 2,4-D .0001 Endothall .009 Endrin .00001 Ethylene dibromide (EDB) .00001 Glyphosate .006 Heptachlor .00004 Heptachlor epoxide .00002 Hexachlorobenzene .0001 Hexachlorocyclopentadiene .0001 Lindane .00002 Methoxychlor .0001 Oxamyl .002 Picloram .0001 Polychlorinated biphenyls (PCBs) (as decachlorobiphenyl) .0001
Pentachlorophenol .00004 Simazine .00007 

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...(19) Anaylsis under this section shall only be conduc ted by laboratories that have received certification by EPA or the State and have met the following conditions:
(i) To receive certification to conduct analyses fo r the contaminants in §141.61(c) the laboratory must:

(A) Analyze Performance Evaluation (PE) samples provided by EPA, the State, or by a third party (with the approval of the State or EPA) at least once a year by each method for which the laboratory desires certification.

(B) For each contaminant that has been included in the PE sample achieve quantitative results on the analyses that are within the following acceptance limits:

(ii) [Reserved]
(20) All new systems or systems that use a new source of water that begin operation after January 22, 2004 must demonstrate compliance with the MCL within a period of time specified by the State. The system must also comply with the initial sampling fr equencies specified by the State to ensure a system can demonstrate compliance with the MCL. Routine and increased monitoring frequencies shall be conducted in accordance with the requirements in this section.
(Approved by the Office of Management and Budget under control number 2040–0090)

[40 FR 59570, Dec. 24, 1975]

Editorial Note: For Federal Register citations affecting §141.24, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and at www.fdsys.gov.


### § 141.25 Analytical methods for radioactivity.

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(a) Analysis for the following contaminants shall be conducted to determine compliance with §141.66 (radioactivity) in accordance with the methods in the fo llowing table, or the alternative methods listed in appendix A to subpart C this part, or their equivalent determined by EPA in accordance with §141.27. 

## Toxaphene .001 2,3,7,8-TCDD (Dioxin) .000000005 2,4,5-TP (Silvex) .0002

Contaminant Acceptance limits (percent) DBCP ±40 EDB ±40. Alachlor ±45. Atrazine ±45. Benzo[a]pyrene 2 standard deviations. Carbofuran ±45. Chlordane ±45. Dalapon 2 standard deviations. Di(2-ethylhexyl)adipate 2 standard deviations. Di(2-ethylhexyl)phthalate 2 standard deviations. Dinoseb 2 standard deviations. Diquat 2 standard deviations. Endothall 2 standard deviations. Endrin ±30. Glyphosate 2 standard deviations. Heptachlor ±45. Heptachlor epoxide ±45. Hexachlorobenzene 2 standard deviations. Hexachloro- cyclopentadiene 2 standard deviations. Lindane ±45. Methoxychlor ±45. Oxamyl 2 standard deviations. PCBs (as Decachlorobiphenyl) 0–200. Picloram 2 standard deviations. Simazine 2 standard deviations. Toxaphene ±45. Aldicarb 2 standard deviations. Aldicarb sulfoxide 2 standard deviations. Aldicarb sulfone 2 standard deviations. Pentachlorophenol ±50. 2,3,7,8-TCDD (Dioxin) 2 standard deviations. 2,4-D ±50. 2,4,5-TP (Silvex) ±50. 

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...

## Contaminant Methodology Reference (Method of Page Number) EPA 1 

## EPA 2 

## EPA 3 

## EPA4 

## SM 5 

## ASTM 6 

## USGS 7 

## DOE 8 

## Other Naturally Occurring: Gross alpha 11 

## and beta Evaporation 900.0 p. 1 00– 01 p. 1 302, 7110 B, 7110 B–00 R– 1120– 76

Gross alpha 11 

## Coprecipitation 00– 02 7110 C, 7110 C–00 Radium 226 Radon emanation 903.1 p. 16 Ra– 04 p. 19 305, 7500– Ra C, 7500– Ra C–01 D3454–97 R– 1141– 76 Ra-04 NY 9



## ,

Radiochemical 903.0 p. 13 Ra03 304, 7500– Ra B, 7500– Ra B– 01 D2460–97 R– 1140– 76 GA 14



## Radium 228 Radiochemical 904.0 p. 24 Ra05 p. 19 7500– Ra D, 7500– Ra D–01 R– 1142– 76 NY 9



## , NJ 10



## , GA 14



## Uranium 12 

## Radiochemical 908.0 7500– U B, 7500– U B– 00 Fluorometric 908.1 7500– U C (17th Ed.) D2907–97 R– 1180– 76, R– 1181– 76 U–04

ICP–MS 200.8 13 

## 3125 D5673–03 Alpha Spectrometry 00– 07 p. 33 7500– U C (18th, 19th, or 20th Ed.), 7500– U C– 00 D3972–97, 02 R– 1182– 76 U–02

Laser Phosphorimetry D5174–97, 02 Man-Made: Radioactive Cesium Radiochemical 901.0 p. 4 7500– Cs B, 7500– Cs B– 00 D2459–72 R– 1111– 76

Gamma Ray Spectrometry 901.1 p. 92 7120, 7120– 97 D3649–91, 98a R– 1110– 76 4.5.2.3

Radioactive Iodine Radiochemical 902.0 p. 6 7500– I B, 7500– I B– 00 p. 9 7500– I C, 7500– I C– 00 7500– D3649–91, 

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...The procedures shall be done in accordance with the documents listed below. The incorporation by reference of documents 1 through 10 and 13 through 14 was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) a nd 1 CFR part 51. Copies of the documents may be obtained from the sources listed below. Informati on regarding obtaining thes e documents can be obtained from the Safe Drinking Water Hotline at 800–426–4791. Documents may be inspected at EPA's Drinking Water Docket, EPA West, 1301 Constitution Avenue, NW., Room 3334 , Washington, DC 20460 (Telephone: 202–566–2426); or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202–741–6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

1 “Prescribed Procedures for the Measurement of Radioactivity in Drinking Water,” EPA 600/4–80–032, A ugust 1980. Available at the U.S. Department of Commerce, National Technical Information Service (NTIS), 5285 Port Royal Road, Springfield, VA 22161 (Telephone 800–553–6847), PB 80–224744.

2 “Interim Radiochemical Methodology for Drin king Water,” EPA 600/4–75–008 (revised), March 1976. Available NTIS, ibid.

3 “Radiochemistry Procedures Manual,” EPA 520/5–84–006, December 1987. Available NTIS, ibid.

4 “Radiochemical Analytical Procedures for Analysis of Environmental Samples,” March 1979. Available at NTIS, ibid. EMSL LV 053917.

5 “Standard Methods for the Examination of Water and Wastewater,” 13th, 17th, 18th, 19th or 20th edition, 1971, 1989, 1992, 1995, 1998. Available at Amer ican Public Health Association, 1015 Fifteenth Street, NW., Washington, DC 20005. Methods 302, 303, 304, 305 and 306 are only in the 13th edition. Methods 7110B, 7500–Ra B, 7500–Ra C, 7500–Ra D, 7500–U B, 7500–Cs B, 7500–I B, 7500–I C, 7500–I D, 7500–Sr B, and 7500– 3 H B are in the 17th, 18th, 19th and 20th editions. Method 7110 C is in the 18th, 19th and 20th editions. Method 7500–U C Fluorometric Uranium is only in the 17th Edition, and 7500–U C Alpha spectrometry is only in the 18th, 19th and 20th editions. Method 7120 is only in the 19th and 20th editions. Method 3125 is only in the 20th edition. Methods 7110 B–00, 7110 C–00, 7500– Ra B–01, 7500–Ra C–01, 7500–Ra D–01, 7500–U B–00, 7500–U C–00, 7500–I B–00, 7500–I C–00, 7500–I D–00, 7120–97, 7500–Sr B–01, and 7500– 3 H B–00 are available online at http://www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only online versions that may be used.

6 Annual Book of ASTM Standards, Vol. 11.01 and 11.02, 2002; ASTM International; any year containing the cited version of the method may be used. Copies of these two volumes and the 2003 version of D 5673–03 may be obtained from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428–2959.

7 “Methods for Determination of Radioactive Substances in Water and Fluvial Sediments,” Chapter A5 in Book 5 of Techniques of Water-Resource s Investigations of the United States Geological Survey, 1977. Available at U.S. Geological Survey (USGS) Information Services, Box 25286, Federal Center, Denver, CO 80225–0425.

8 “EML Procedures Manual,” 28th (1997) or 27th (1990) Editions, Volumes 1 and 2; either edition may be used. In the 27th Edition Method Ra-04 is listed as Ra-05 and Method Ga-01–R is listed as Sect. 4.5.2.3. Available at the Environmental Measurements Laboratory, U.S. Department of Energy (DOE), 376 Hudson Street, New York, NY 10014–3621. 

## I D, 7500– I D– 00 98a

Gamma Ray Spectrometry 901.1 p. 92 7120, 7120– 97 D4785–93, 00a 4.5.2.3

Radioactive Strontium 89, 90 Radiochemical 905.0 p. 29 Sr– 04 p. 65 303, 7500– Sr B, 7500– Sr B– 01 R– 1160– 76 Sr–01, Sr–02

Tritium Liquid Scintillation 906.0 p. 34 H–02 p. 87 306, 7500– 3 

## H B, 7500– 3 

## H B– 00 D4107–91, 98 (Reapproved 2002) R– 1171– 76

Gamma Emitters Gamma Ray Spectrometry 901.1 p. 92 7120, 7120– 97 D3649–91, 98a R– 1110– 76 Ga– 01–R

902.0 7500– Cs B, 7500– Cs B– 00 D4785–93, 00a

901.0 7500– I B, 7500– I B– 00 

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...9 “Determination of Ra–226 and Ra–228 (Ra–02),” Janu ary 1980, Revised June 1982. Available at Radiological Sciences Institute for Laboratories and Research, New York State Department of Health, Empire State Plaza, Albany, NY 12201.

10 “Determination of Radium 228 in Drinking Water,” August 1980. Available at State of New Jersey, Department of Environmental Protection, Division of Environmental Quality, Bureau of Radiation and Inorganic Analytical Services, 9 Ewing Street, Trenton, NJ 08625.

11 Natural uranium and thorium-230 are approved as gross alpha calibration standards for gross alpha with co-precipitation and evaporation methods; americium-241 is approved with co-precipitation methods.

12 If uranium (U) is determined by mass, a 0.67 pCi/ μ g of uranium conversion fac tor must be used. This conversion factor is based on the 1:1 activity rati o of U–234 and U–238 that is characteristic of naturally occurring uranium.

13 “Determination of Trace Elements in Waters and Wastes by Inductively Coupled Plasma-Mass Spectrometry,” Revision 5.4, which is published in “Methods for the Determination of Metals in Environmental Samples—Supplement I,”' EPA 600–R–94–111, May 1994. Available at NTIS, PB 95– 125472.

14 “The Determination of Radium-226 and Radium-228 in Drinking Water by Gamma-ray Spectrometry Using HPGE or Ge(Li) Detectors,” Revision 1.2, De cember 2004. Available from the Environmental Resources Center, Georgia Institute of Technology, 620 Cherry Street, Atlanta, GA 30332–0335, USA, Telephone: 404–894–3776. This method may be used to analyze for radium-226 and radium-228 in samples collected after January 1, 2005 to satisfy the radium-226 and radium-228 monitoring requirements specified at 40 CFR 141.26.
(b) When the identification and measurement of radion uclides other than those listed in paragraph (a) of this section is required, the following references are to be used, except in cases where alternative methods have been approved in accordance with §141.27.

(1) Procedures for Radiochemic al Analysis of Nuclear R eactor Aqueous Solutions, H. L. Krieger and S. Gold, EPA-R4–73–014. USEPA, Cincinnati, Ohio, May 1973.

(2) HASL Procedure Manual, Edited by John H. Harley. HASL 300, ERDA Health and Safety Laboratory, New York, NY., 1973.
(c) For the purpose of monitoring radioac tivity concentrations in drinking water, the required sensitivity of the radioanalysis is defined in terms of a detection limit. The detection limit s hall be that concentration which can be counted with a precis ion of plus or minus 100 percentat the 95 percent confidence level (1.96 σwhere σis the standard deviation of the net counting rate of the sample).
(1) To determine compliance with §141.66(b), (c), and (e) the detection limit shall not exceed the concentrations in Table B to this paragraph.
Table B—Detection Limits for Gross Alpha Particle Activity, Radium 226, Radium 228, and Uranium

(2) To determine compliance with §141.66(d) the detecti on limits shall not exceed the concentrations listed in Table C to this paragraph.

Table C—Detection Limits for Man-made Beta Particle and Photon Emitters

(d) To judge compliance with the maximum contamina nt levels listed in §141.66, averages of data shall be used and shall be rounded to the same number of significant figures as the maximum contaminant level for the substance in question.
(e) The State has the authority to determine compliance or initiate enforcement action based upon analytical results or other information compiled by their sanctioned representatives and agencies.

[41 FR 28404, July 9, 1976, as amended at 45 FR 57345, Aug. 27, 1980; 62 FR 10173, Mar. 5, 1997; 65 FR 76745, Dec. 7, 2000; 67 FR 65250, Oct. 23, 2002; 69 FR 38855, June 29, 2004; 69 FR 52180, Aug. 25, 2004; 72 FR 11245, Mar. 12, 2007; 74 FR 30958, June 29, 2009]


### § 141.26 Monitoring frequency and compliance requirements for radionuclides in community water systems. 

## Contaminant Detection limit Gross alpha particle activity 3 pCi/L. Radium 226 1 pCi/L. Radium 228 1 pCi/L. Uranium 1 μg/L

Radionuclide Detection limit Tritium 1,000 pCi/1. Strontium–89 10 pCi/1. Strontium–90 2 pCi/1. Iodine–131 1 pCi/1. Cesium–134 10 pCi/1. Gross beta 4 pCi/1. Other radionuclides 1/10 of the applicable limit. 

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...top
(a) Monitoring and compliance requirements for gross alpha particle activity, radium-226, radium-228, and uranium. (1) Community water systems (CWSs) mustconduct initial monitoring to determine compliance with §141.66(b), (c), and (e) by Dece mber 31, 2007. For the purposes of monitoring for gross alpha particle activity, radium-226, radium-228, uranium, and beta particle and photon radioactivity in drinking water, “detection limit” is defined as in §141.25(c).
(i) Applicability and sampling location for ex isting community water systems or sources. All existing CWSs using ground water, surface water or systems using both ground and surface water (for the purpose of this section hereafter referred to as systems) must sample at every entry point to the distribution system that is representative of all sources being used (hereafter called a sampling point) under normal operating conditions. The system must take each sample at the same sampling point unless conditions make another sampling point more representative of each source or the State has designated a distribution system lo cation, in accordance with paragraph (a)(2)(ii)(C) of this section.
(ii) Applicability and sampling location for new community water systems or sources. All new CWSs or CWSs that use a new source of water must begin to c onduct initial monitoring for the new source within the first quarter after initiating use of the source. CWSs must conduct more frequent monitoring when ordered by the State in the event of possible contam ination or when changes in the distribution system or treatment processes occur which may increase the c oncentration of radioactivity in finished water.
(2) Initial monitoring: Systems must conduct initial monitoring forgross alpha particle activity, radium226, radium-228, and uranium as follows:
(i) Systems without acceptable hist orical data, as defined below, must coll ect four consecutive quarterly samples at all sampling points before December 31, 2007.
(ii) Grandfathering of data: States may allow historical monitoring data collected at a sampling point to satisfy the initial monitoring requirements for that sampling point, for the following situations.

(A) To satisfy initial monitoring requirements, a co mmunity water system having only one entry point to the distribution system may use the monitoring data from the last compliance monitoring period that began between June 2000 and December 8, 2003.
(B) To satisfy initial monitoring requirements, a community water system with multiple entry points and having appropriate historical monitoring data for ea ch entry point to the distri bution system may use the monitoring data from the last compliance monitoring period that began between June 2000 and December 8, 2003.
(C) To satisfy initial monitoring requirements, a co mmunity water system with appropriate historical data for a representative point in the distribution sys tem may use the monitoring data from the last compliance monitoring period that began between J une 2000 and December 8, 2003, provided that the State finds that the historical data satisfactorily demonstrate that each entry point to the distribution system is expected to be in compliance based up on the historical data and reasonable assumptions about the variability of contaminant levels between entry points. The State must make a written finding indicating how the data conforms to the these requirements.
(iii) For gross alpha particle acti vity, uranium, radium-226, and radium-228 monitoring, the State may waive the final two quarters of initial monitoring for a sampling point if the results of the samples from the previous two quarters are below the detection limit.
(iv) If the average of the initial monitoring results for a sampling point is above the MCL, the system must collect and analyze quarterly samples at that sampling point until the system has results from four consecutive quarters that are at or below the MCL, unless the system enters into another schedule as part of a formal compliance agreement with the State.
(3) Reduced monitoring: States may allow community water systems to reduce the future frequency of monitoring from once every three years to once every six or nine years at each sampling point, based on the following criteria.
(i) If the average of the initial monitoring results for each contaminant ( i.e., gross alpha particle activity, uranium, radium-226, or radium-228) is below the detecti on limit specified in Table B, in §141.25(c)(1), the system must collect and analyze for that contaminant using at least one sample at that sampling point every nine years.
(ii) For gross alpha particle activityand uranium, if the average of the initial monitoring results for each contaminant is at or above the detection limit but at or below1/2the MCL, the system must collect and analyze for that contaminant using at least one samp le at that sampling point every six years. For combined radium-226 and radium-228, the analytical results must be combined. If the average of the combined initial monitoring results for radium-226 an d radium-228 is at or above the detection limit but at or below1/2the MCL, the system must collect a nd analyze for that contamin ant using at least one sample at that sampling point every six years.
(iii) For gross alpha particle activity and uranium, if the average of the initial monitoring results for each contaminant is above1/2the MCL but at or below the MCL, the system must collect and analyze at least one sample at that sampling point every three years. For combined radium-226 and radium-228, theanalytical results must be combined. If the average of the combined initial monitoring results for radium226 and radium-228 is above1/2the MCL but at or below the MCL, the system must collect and analyze at least one sample at that sampling point every three years.
(iv) Systems must use the samples collected du ring the reduced monitoring period to determine the monitoring frequency for subsequent monitoring periods (e.g., if a system's sampling point is on a nine year monitoring period, and the sample result is above1/2MCL, then the next monitoring period for that sampling point is three years).
(v) If a system has a monitoring result that exceeds the MCL while on reduced monitoring, the system must collect and analyze quarterly samples at that sampling point until the system has results from four consecutive quarters that are below the MCL, unless the system enters into another schedule as part of a formal compliance agreement with the State.
(4) Compositing: To fulfill quarterly monitoring requirements fo r gross alpha particle activity, radium-226, radium-228, or uranium, a system may composite up to four consecutive quarterly samples from a single entry point if analysis is done within a year of the fi rst sample. States will treat analytical results from the composited as the average analytic al result to determine compliance with the MCLs and the future 

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...monitoring frequency. If the analytical result from the composited sample is greater than1/2MCL, the State may direct the system to take additional quarter ly samples before allowing the system to sample under a reduced monitoring schedule.
(5) A gross alpha particle activity measurement may be substituted for the required radium-226 measurement provided that the measured gross alpha particle activity does not exceed 5 pCi/l. A gross alpha particle activity measurement may be subs tituted for the required uranium measurement provided that the measured gross alpha particle activity does not exceed 15 pCi/l. The gross alpha measurement shall have a confidence interval of 95% (1.65 σ , where σis the standard deviation of the net counting rate of the sample) for radium-226 and uranium. When a system uses a gross alpha particle activity measurement in lieu of a radium-226 and/or uraniu m measurement, the gross al pha particle activity analytical result will be used to determine the future monitoring frequency for radium-226 and/or uranium. If the gross alpha particle activity result is less than detection,1/2the detection limit will be used to determine compliance and the future monitoring frequency.
(b) Monitoring and compliance requirements for beta particle and photon radioactivity. To determine compliance with the maximum contaminant levels in §141.66(d) for beta particle and photon radioactivity, a system must monitor at a frequency as follows:

(1) Community water systems (both surface and ground water) designated by the State as vulnerable must sample for beta particle and photon radioactivity . Systems must collect quarterly samples for beta emitters and annual samples for tritium and strontium-90 at each entry point to the distribution system (hereafter called a sampling point), beginning wi thin one quarter after being notified by the State. Systems already designated by the State must continue to sample until the State reviews and either reaffirms or removes the designation.
(i) If the gross beta particle activityminus the naturally occurring potass ium-40 beta particle activity at a sampling point has a running annual average (com puted quarterly) less than or equal to 50 pCi/L (screening level), the State may reduce the frequency of monitoring at that sampling point to once every 3 years. Systems must collect all samples required in paragraph (b)(1) of this section during the reduced monitoring period.
(ii) For systems in the vicinityof a nuclear facility, the State may allow the CWS to utilize environmental surveillance data collected by the nuc lear facility in lieu of monitoring at the system's entry point(s), where the State determines if such data is applicable to a particular water system. In the event that there is a release from a nuclear facility, systems which are using surveillance data must begin monitoring at the community water system's entry point(s) in accordance with paragraph (b)(1) of this section.

(2) Community water systems (both surface and grou nd water) designated by the State as utilizing waters contaminated by effluents from nuclear facil ities must sample for beta particle and photon radioactivity. Systems must collect quarterly samples for beta emitters and iodine-131 and annual samples for tritium and strontium-90 at each entry point to the distribution system (hereafter called a sampling point), beginning within one quarter after being notified by the State. Systems already designated by the State as systems using waters co ntaminated by effluents from nuclear facilities must continue to sample until the State reviews and either reaffirms or removes the designation.
(i) Quarterly monitoring for gross b eta particle activity shall be bas ed on the analysis of monthly samples or the analysis of a composite of three monthly samples. The former is recommended.

(ii) For iodine-131, a composite of five consecutive daily samples shall be analyzed once each quarter. As ordered by the State, more frequent monitoring shal l be conducted when iodine-131 is identified in the finished water.

(iii) Annual monitoring for strontium-90 and tritiu m shall be conducted by means of the analysis of a composite of four consecutive quarterly samples or analysis of four quarterly samples. The latter procedure is recommended.
(iv) If the gross beta particle activi ty minus the naturally occurring potassi um-40 beta particle activity at a sampling point has a running annual average (com puted quarterly) less than or equal to 15 pCi/L (screening level), the State may reduce the frequency of monitoring at that sampling point to every 3 years. Systems must collect the same type of samples required in paragraph (b)(2) of this section during the reduced monitoring period.
(v) For systems in the vicinity of a nuclear facility, the State may allow the CWS to utilize environmental surveillance data collected by the nuc lear facility in lieu of monitoring at the system's entry point(s), where the State determines if such data is applicable to a particular water system. In the event that there is a release from a nuclear facility, systems which are using surveillance data must begin monitoring at the community water system's entry point(s) in accordance with paragraph (b)(2) of this section.
(3) Community water systems des ignated by the State to monitor for beta particle and photon radioactivity can not apply to the State for a waiver from the monitoring frequencies specified in paragraph (b)(1) or (b)(2) of this section.
(4) Community water systems may analyze for natural ly occurring potassium-40 beta particle activity from the same or equivalent sample used for the gross beta particle activity analysis. Systems are allowed to subtract the potassium-40 beta particle activityvalue from the total gross beta particle activity value to determine if the screening level is exceeded. The potassium-40 beta particle activity must be calculated by multiplying elemental potassium concentrations (in mg/L) by a factor of 0.82.
(5) If the gross beta particle activity minus the naturally occurring potassium-40 beta particle activity exceeds the appropriate screening level, an analysis of the sample must be performed to identify the major radioactive constituen ts present in the sample and the appropriate doses must be calculated and summed to determine compliance with §141.66(d)(1), using the formula in §141.66(d)(2). Doses must also be calculated and combined for measured levels of tritium and strontium to determine compliance.
(6) Systems must monitor monthly at the sampling point(s) which exceed the maximum contaminant level in §141.66(d) beginning the month after the exceedance occurs. Systems must continue monthly monitoring until the system has established, by a rolling average of 3 monthly samples, that the MCL is being met. Systems who establish that the MCL is being met must return to quarterly monitoring until they meet the requirements set forth in paragraph (b)(1)(i) or (b)(2)(iv) of this section.
(c) General monitoring and compliance requirements for radionuclides. (1) The State may require more frequent monitoring than specified in paragraphs (a) and (b) of this section, or may require confirmation samples at its discretion. The results of the initial and confirmation samples will be averaged for use in compliance determinations. 

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...(2) Each public water systems shall monitor at the time designated by the State during each compliance period.
(3) Compliance: Compliance with §141.66 (b) through (e) will be determined based on the analytical result(s) obtained at each sampling point. If one sampling point is in violation of an MCL, the system is in violation of the MCL.
(i) For systems monitoring more than once per y ear, compliance with the MCL is determined by a running annual average at each sampling point. If the average of any sampling point is greater than the MCL, then the system is out of compliance with the MCL.
(ii) For systems monitoring more than once per year, if any sample result will cause the running average to exceed the MCL at any sample point, the system is out of compliance with the MCL immediately.
(iii) Systems must include all samples taken and analyzed under the provisions of this section in determining compliance, even if that number is greater than the minimum required.
(iv) If a system does not collect all required samples when compliance is based on a running annual average of quarterly samples, compliance will be based on the running average of the samples collected.
(v) If a sample result is less than the detection limit, zero will be used to calculate the annual average, unless a gross alpha particle activity is being used in lieu of radium-226 and/or uranium. If the gross alpha particle activity result is less than detect ion,1/2the detection limit will be used to calculate the annual average.
(4) States have the discretion to delete results of obvious sampling or analytic errors.
(5) If the MCL for radioactivity set forth in §141 .66 (b) through (e) is exceeded, the operator of a community water system must give notice to the Stat e pursuant to §141.31 and to the public as required by subpart Q of this part.

[65 FR 76745, Dec. 7, 2000, as amended at 69 FR 38855, June 29, 2004]


### § 141.27 Alternate analytical techniques.

top
(a) With the written permission of the State, concur red in by the Administrator of the U.S. EPA, an alternate analytical technique may be employed. An al ternate technique shall be accepted only if it is substantially equivalent to the prescribed test in both precision and accuracy as it relates to the determination of compliance with any MCL. The us e of the alternate analytical technique shall not decrease the frequency of monitoring required by this part.

[45 FR 57345, Aug. 27, 1980]


### § 141.28 Certified laboratories.

top
(a) For the purpose of determining compliance with §141.21 through 141.27, 141.30, 141.40, 141.74, 141.89 and 141.402, samples may be considered only if they have been analyzed by a laboratory certified by the State except that measurements of alka linity, calcium, conductivi ty, disinfectant residual, orthophosphate, pH, silica, temperature and turbidity may be performed by any person acceptable to the State.
(b) Nothing in this part shall be construed to precl ude the State or any duly designated representative of the State from taking samples or from using the resu lts from such samples to determine compliance by a supplier of water with the applicable requirements of this part.

[45 FR 57345, Aug. 27, 1980; 47 FR 10999, Mar. 12, 1982, as amended at 59 FR 34323, July 1, 1994; 64 FR 67465, Dec. 1, 1999; 71 FR 65651, Nov. 8, 2006]


### § 141.29 Monitoring of consecutive public water systems.

top
When a public water system supplies water to one or more other public water systems, the State may modify the monitoring requirements imposed by this part to the extent that the interconnection of the systems justifies treating them as a single system for monitoring purposes. Any modified monitoring shall be conducted pursuant to a schedule specified bythe State and concurred in by the Administrator of the U.S. Environmental Protection Agency.


### Appendix A to Subpart C of Part 141—Alternative Testing Methods Approved for Analyses Under the Safe Drinking Water Act

top
Only the editions stated in the following table are approved.

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.21(f)(3)



## Organism Methodology SM 21st edition 1 

## Other Total Coliforms Total Coliform Fermentation Technique 9221 A, B 

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...Alternative Testing Methods for Contaminants Listed at 40 CFR 141.21(f)(6)

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.23(k)(1) 

## Total Coliform Membrane Filter Technique 9222 A, B, C
Presence-Absence (P–A) Coliform Test 9221 D

ONPG–MUG Test 9223 Colitag TM 

## Modified Colitag TM13



## Organism Methodology SM 20th edition 6 

## SM 21st edition 1 

## SM online 3 

## Other E. coli ONPG–MUG Test 9223 B 9223 B 9223 B– 97 Modified Colitag TM13



## Contaminant Methodology EPA method SM 21st edition 1 

## SM online 3 

## ASTM 4 

## Other Alkalinity Titrimetric 2320 B D 1067– 06 B Antimony Hydride—Atomic Absorption D 3697– 07 Atomic Absorption; Furnace 3113 B 3113 B–04 Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2. 2 

## Arsenic Atomic Absorption; Furnace 3113 B 3113 B–04 D 2972– 08 C Hydride Atomic Absorption 3114 B 3114 B–09 D 2972– 08 B Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2. 2 

## Barium Inductively Coupled Plasma 3120 B Atomic Absorption; Direct 3111 D Atomic Absorption; Furnace 3113 B 3113 B–04 Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2. 2 

## Beryllium Inductively Coupled Plasma 3120 B Atomic Absorption; Furnace 3113 B 3113 B–04 D 3645– 08 B Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2. 2 

## Cadmium Atomic Absorption; Furnace 3113 B 3113 B–04 Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2. 2 

## Calcium EDTA titrimetric 3500– Ca B D 511– 09 A Atomic Absorption; Direct Aspiration 3111 B D 511– 09 B Inductively Coupled Plasma 3120 B Axially viewed inductively coupled 200.5, 

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...

## plasma-atomic emission spectrometry (AVICP–AES) Revision 4.2. 2 

## Ion Chromatography D 6919– 09 Chromium Inductively Coupled Plasma 3120 B Atomic Absorption; Furnace 3113 B 3113 B–04 Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2. 2 

## Copper Atomic Absorption; Furnace 3113 B 3113 B–04 D 1688– 07 C Atomic Absorption; Direct Aspiration 3111 B D 1688– 07 A Inductively Coupled Plasma 3120 B Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2. 2 

## Conductivity Conductance 2510 B Cyanide Manual Distillation followed by D2036– 06 A Spectrophotometric, Amenable 4500– CN − 

## G D2036– 06 B Spectrophotometric Manual 4500– CN − 

## E D2036– 06 A Selective Electrode 4500– CN − 

## F Gas Chromatography/Mass Spectrometry Headspace ME355.01 7



## Fluoride Ion Chromatography 4110 B Manual Distillation; Colorimetric SPADNS 4500–F 

## B, D Manual Electrode 4500– F–C D 1179– 04 B Automated Alizarin 4500– F–E Arsenite-Free Colorime tric SPADNS Hach SPADNS 2 Method 10225. 22 

## Lead Atomic Absorption; Furnace 3113 B 3113 B–04 D 3559– 08 D Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2. 2 

## Magnesium Atomic Absorption; Direct 3111 B D 511– 09 B Inductively Coupled Plasma 3120 B Complexation Titrimetric Methods 3500– Mg B D 511– 09 A Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2 2 

## Ion Chromatography D 6919– 09 Mercury Manual, Cold Vapor 3112 B Nickel Inductively Coupled Plasma 3120 B Atomic Absorption; Direct 3111 B Atomic Absorption; Furnace 3113 B 3113 B–04 Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2. 2 

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...Alternative Testing Methods for Contaminants Listed at 40 CFR 141.24(e)(1) 

## Nitrate Ion Chromatography 4110 B Automated Cadmium Reduction 4500– NO 3 

## –F Manual Cadmium Reduction 4500– NO 3 

## –E Ion Selective Electrode 4500– NO 3 

## –D Reduction/Colorimetric Systea Easy (1– Reagent). 8 

## Colorimetric; Direct Hach TNTplus TM 

## 835/836 Method 10206. 23 

## Nitrite Ion Chromatography 4110 B Automated Cadmium Reduction 4500– NO 3 − 

## F Manual Cadmium Reduction 4500– NO 3 − 

## E Spectrophotometric 4500– NO 2 − 

## B Reduction/Colorimetric Systea Easy (1-Reagent) 8 

## Orthophosphate Ion Chromatography 4110 B Colorimetric, ascorbic acid, single reagent 4500–P E 4500– P E–99 Colorimetric, Automated, Ascorbic Acid 4500–P F 4500– P F–99 pH Electrometric 4500– H + 

## B Selenium Hydride—Atomic Absorption 3114 B 3114 B–09 D 3859– 08 A Atomic Absorption; Furnace 3113 B 3113 B–04 D 3859– 08 B Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2. 2 

## Silica Colorimetric D859– 05 Molybdosilicate 4500– SiO 2 

## C Heteropoly blue 4500– SiO 2 

## D Automated for Molybdate-reactive Silica 4500– SiO 2 

## E Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2. 2 

## Inductively Coupled Plasma 3120 B Sodium Atomic Absorption; Direct Aspiration 3111 B Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2 2 

## Ion Chromatography D 6919– 09 Temperature Thermometric 2550

Contaminant Methodology EPA method SM 21st edition 1 

## SM online 3 

## Benzene Purge & Trap/Gas 524.3 9 

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...

## Chromatography/Mass Spectrometry Carbon tetrachloride Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

Chlorobenzene Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

1,2-Dichlorobenzene Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

1,4-Dichlorobenzene Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

1,2-Dichloroethane Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

cis-Dichloroethylene Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

TransDichloroethylene Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

Dichloromethane Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

1,2-Dichloropropane Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

Ethylbenzene Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

Styrene Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

Tetrachloroethylene Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

1,1,1-Trichloroethane Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

Trichloroethylene Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

Toluene Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

1,2,4- Trichlorobenzene Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

1,1-Dichloroethylene Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

1,1,2-Trichlorethane Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

Vinyl chloride Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

Xylenes (total) Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

2,4-D Gas Chromatography/Electron Capture Detection (GC/ECD) 6640 B 6640 B–01

2,4,5-TP (Silvex) Gas Chromatography/Electron Capture Detection (GC/ECD) 6640 B 6640 B–01

Carbofuran High-performance liquid chromatography (HPLC) 6610 B 6610 B–04 

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...Alternative Testing Methods for Contaminants Listed at 40 CFR 141.25(a) 

## with post-column derivatization and fluorescence detection Dalapon Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC–ESI– MS/MS) 557 14



## Gas Chromatography/Electron Capture Detection (GC/ECD) 6640 B 6640 B–01

Dibromochloropropane (DBCP) Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

Dinoseb Gas Chromatography/Electron Capture Detection (GC/ECD) 6640 B 6640 B–01

Ethyl dibromide (EDB) Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

Glyphosate High-Performance Liquid Chromatography (HPLC) with Post-Column Derivatization and Fluorescence Detection 6651 B 6651 B–00

Oxamyl High-performance liquid chromatography (HPLC) with post-column derivatization and fluorescence detection 6610 B 6610 B–04

Pentachlorophenol Gas Chromatography/Electron Capture Detection (GC/ECD) 6640 B 6640 B–01

Picloram Gas Chromatography/Electron Capture Detection (GC/ECD) 6640 B 6640 B–01

Total Trihalomethanes Purge & Trap/Gas Chromatography/Mass Spectrometry 524.3

Contaminant Methodology SM 21st edition 1 

## ASTM 4 

## Naturally Occurring: Gross alpha and beta Evaporation 7110 B Gross alpha Coprecipitation 7110 C Radium 226 Radon emanation 7500–Ra C D3454– 05 Radiochemical 7500–Ra B D2460– 07 Radium 228 Radiochemical 7500–Ra D Uranium Radiochemical 7500–U B ICP–MS D5673– 05 Alpha spectrometry 7500–U C D3972– 09 Laser Phosphorimetry D5174– 07 Man-Made: Radioactive Cesium Radiochemical 7500–Cs B Gamma Ray Spectrometry 7120 D3649– 06 Radioactive Iodine Radiochemical 7500–I B D3649– 

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...Alternative Testing Methods for Contaminants Listed at 40 CFR 141.74(a)(1)

Alternative Testing Methods for Disinfectant Residuals Listed at 40 CFR 141.74(a)(2) 

## 06 7500–I C 7500–I D Gamma Ray Spectrometry 7120 D4785– 08 Radioactive Strontium 89, 90 Radiochemical 7500–Sr B Tritium Liquid Scintillation 7500 − 3 

## H B D4107– 08 Gamma Emitters Gamma Ray Spectrometry 7120 D3649– 06 7500–Cs B D4785– 08 7500–I B

Organism Methodology SM 21st edition 1 

## Other Total Coliform Total Coliform Fermentation Technique 9221 A, B, C Total Coliform Membrane Filter Technique 9222 A, B, C ONPG–MUG Test 9223 Fecal Coliforms Fecal Coliform Procedure 9221 E Fecal Coliform Filter Procedure 9222 D
Heterotrophic bacteria Pour Plate Method 9215 B
Turbidity Nephelometric Method 2130 B Laser Nephelometry (on-line) Mitchell M5271 10 

## LED Nephelometry (on-line) Mitchell M5331 11 

## LED Nephelometry (on-line) AMI Turbiwell 15 

## LED Nephelometry (portable) Orion AQ4500 12



## Residual Methodology SM 21st Edition 1 

## ASTM 4 

## Other Free Chlorine Amperometric Titration 4500–Cl D D 1253– 08 DPD Ferrous Titrimetric 4500–Cl F DPD Colorimetric 4500–Cl G Syringaldazine (FACTS) 4500–Cl H On-line Chlorine Analyzer EPA 334.0. 16 

## Amperometric Sensor ChloroSense. 17 

## Total Chlorine Amperometric Titration 4500–Cl D D 1253– 08 Amperometric Titration (Low level measurement) 4500–Cl E

DPD Ferrous Titrimetric 4500–Cl F DPD Colorimetric 4500–Cl G Iodometric Electrode 4500–Cl I On-line Chlorine Analyzer EPA 334.0. 16 

## Amperometric Sensor ChloroSense. 17 

## Chlorine Dioxide Amperometric Titration 4500– ClO 2 

## C Amperometric Titration 4500– ClO 2 

## E Ozone Indigo Method 4500–O 3 

## B 

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...Alternative Testing Methods for Contaminants Listed at 40 CFR 141.131(b)(1)

Alternative Testing Methods for Disinfectant Residuals Listed at 40 CFR 141.131(c)(1)

Alternative Testing Methods for Disinfectant Residuals Listed at 40 CFR 141.131(c)(2), If 

## Contaminant Methodology EPA Method ASTM 4 

## SM 21st Edition 1 

## TTHM P&T/GC/MS 9 

## 524.3 HAA5 LLE (diazomethane)/GC/ECD 6251 B. Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC–ESI–MS/MS) 14 

## 557

Bromate Two-Dimensional Ion Chromatography (IC) 18 

## 302.0 Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC–ESI–MS/MS) 14 

## 557

Chemically Suppressed Ion Chromatography D 6581– 08 A. Electrolytically Suppressed Ion Chromatography D 6581– 08 B. Chlorite Chemically Suppressed Ion Chromatography D 6581– 08 A. Electrolytically Suppressed Ion Chromatography D 6581– 08 B. Chlorite—daily monitoring as prescribed in 40 CFR 141.132(b) (2)(i)(A). Amperometric Titration 4500– ClO 2 

## E.

Residual Methodology SM 21st Edition 1 

## ASTM 4 

## Other Free Chlorine Amperometric Titration 4500–Cl D D 1253– 08 DPD Ferrous Titrimetric 4500–Cl F

DPD Colorimetric 4500–Cl G Syringaldazine (FACTS) 4500–Cl H
Amperometric Sensor ChloroSense. 17 

## On-line Chlorine Analyzer EPA 334.0. 16



## Combined Chlorine Amperometric Titration 4500–Cl D D 1253– 08 DPD Ferrous Titrimetric 4500–Cl F

DPD Colorimetric 4500–Cl G Total Chlorine Amperometric Titration 4500–Cl D D 1253– 08 Low level Amperometric Titration 4500–Cl E

DPD Ferrous Titrimetric 4500–Cl F

DPD Colorimetric 4500–Cl G Iodometric Electrode 4500–Cl I Amperometric Sensor ChloroSense. 17 

## On-line Chlorine Analyzer EPA 334.0. 16



## Chlorine Dioxide Amperometric Method II 4500– ClO 2 

## E. 

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...Approved by the State

Alternative Testing Methods for Parameters Listed at 40 CFR 141.131(d)

Alternative Testing Methods With MRL ≤0.0010 mg/L for Monitoring Listed at 40 CFR 141.132(b) (3)(ii)(B)

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.402(c)(2)

Alternative Testing Methods for Contaminants Listed at 40 CFR 141.704(b)

Alternative Testing Methods for Contaminants Listed at 40 CFR 143.4(b) 

## Residual Methodology Method Free Chlorine Test Strips Method D99–003 5



## Parameter Methodology SM 21st edition 1 

## EPA Total Organic Carbon (TOC) High Temperature Combustion 5310 B 415.3, Rev 1.2 19 

## Persulfate-Ultraviolet or Heated Persulfate Oxidation 5310 C 415.3, Rev 1.2 Wet Oxidation 5310 D 415.3, Rev 1.2 Specific Ultraviolet Absorbance (SUVA) Calculation using DOC and UV 254 

## data 415.3, Rev 1.2 Dissolved Organic Carbon (DOC) High Temperature Combustion 5310 B 415.3, Rev 1.2 Persulfate-Ultraviolet or Heated Persulfate Oxidation 5310 C 415.3, Rev 1.2 Wet Oxidation 5310 D 415.3, Rev 1.2 Ultraviolet absorption at 254 nm (UV 254 

## ) Spectrophotometry 5910 B 415.3, Rev 1.2

Contaminant Methodology EPA method Bromate Two-Dimensional Ion Chromatography (IC) 302.0 18 

## Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC–ESI–MS/MS) 557 14



## Organism Methodology SM 20th edition 6 

## SM 21st edition 1 

## SM online 3 

## Other E. coli Colilert 9223 B 9223 B– 97 Colisure 9223 B 9223 B– 97 Colilert-18 9223 B 9223 B 9223 B– 97 Readycult® 

## Readycult®



## . 20 

## Colitag Modified Colitag TM



## . 13


## Chromocult® 

## Chromocult®



## . 21 

## Enterococci Multiple-Tube Technique 9230 B– 04

Organism Methodology SM 20th edition 6 

## E. coli Membrane Filtration, Two Step 9222 D/9222 G

Contaminant Methodology EPA method ASTM 4 

## SM 21st edition 1 

## SM online 3 

## Aluminum Axially viewed inductively coupled 200.5, Revision 

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## plasma-atomic emission spectrometry (AVICP–AES) 4.2. 2



## Atomic Absorption; Direct 3111D
Atomic Absorption; Furnace 3113 B 3113 B– 04 Inductively Coupled Plasma 3120 B

Chloride Silver Nitra te Titration D 512– 04 B 4500– Cl − 

## B Ion Chromatography 4110 B Potentiometric Titration 4500– Cl − 

## D Color Visual Comparison 2120 B Foaming Agents Methylene Blue Active Substances (MBAS) 5540 C
Iron Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2 2



## Atomic Absorption; Direct 3111 B
Atomic Absorption; Furnace 3113 B 3113 B– 04 Inductively Coupled Plasma 3120 B
Manganese Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2. 2



## Atomic Absorption; Direct 3111 B
Atomic Absorption; Furnace 3113 B 3113 B– 04 Inductively Coupled Plasma 3120 B

Odor Threshold Odor Test 2150 B Silver Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP–AES) 200.5, Revision 4.2. 2



## Atomic Absorption; Direct 3111 B
Atomic Absorption; Furnace 3113 B 3113 B– 04 Inductively Coupled Plasma 3120 B
Sulfate Ion Chromatography 4110 B Gravimetric with ignition of residue 4500– SO 4 − 2 

## C 4500– SO 4 − 2 

## C– 97 Gravimetric with drying of residue 4500– SO 4 − 2 

## D 4500– SO 4 − 2 

## D– 97 Turbidimetric method D 516– 07 4500– SO 4 − 2 

## E 4500– SO 4 − 2 

## E– 97 Automated methylthymol blue method 4500– SO 4 − 2 

## F 4500– SO 4 − 2 

## F– 97 Total Dissolved Solids Total Dissolved Solids Dried at 180 deg C 2540 C

Zinc Axially viewed 200.5, 

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...1 

### Standard Methods for the Examination of Water and Wastewater , 21st edition (2005). Available from American Public Health Association, 800 I Street, NW., Washington, DC 20001–3710.

2 

### EPA Method 200.5, Revision 4.2. “Determination of Trace Elements in Drinking Water by Axially Viewed Inductively Coupled Plasma-Atomic Emission Spectrometry.” 2003. EPA/600/R–06/115. (Available at http://www.epa.gov/nerlcwww/ordmeth.htm .)

3

### Standard Methods Online are available at http://www.standardmethods.org . The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only online versions that may be used.

4 

### Available from ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428– 2959 or http://astm.org . The methods listed are the only alternative versions that may be used.

5

### Method D99–003, Revision 3.0. “Free Chlorine Species (HOCl − 

### and OCl − 

### ) by Test Strip,” November 21, 2003. Available from Industrial Test Systems, Inc., 1875 Langston St., Rock Hill, SC 29730.

6 

### Standard Methods for the Examination of Water and Wastewater , 20th edition (1998). Available from American Public Health Association, 800 I Street, NW., Washington, DC 20001–3710.

7

### Method ME355.01, Revision 1.0. “Determination of Cyanide in Drinking Water by GC/MS Headspace,” May 26, 2009. Available at http://www.nemi.gov or from James Eaton, H & E Testing Laboratory, 221 State Street, Augusta, ME 04333. (207) 287–2727.

8

### Systea Easy (1-Reagent). “Systea Easy (1-Reagent) Nitrate Method,” February 4, 2009. Available at http://www.nemi.gov or from Systea Scientific, LLC., 900 Jorie Blvd., Suite 35, Oak Brook, IL 60523.

9

### EPA Method 524.3, Version 1.0. “Measurement of Purgeable Organic Compounds in Water by Capillary Column Gas Chromatography/Mass Spectrometry,” June 2009. EPA 815–B–09– 009. Available at http://epa.gov/safewater/methods/analyticalmethods_ogwdw.html

.

10 

### Mitchell Method M5271, Revision 1.1. “Determination of Turbidity by Laser Nephelometry,” March 5, 2009. Available at http://www.nemi.gov or from Leck Mitchell, PhD, PE, 656 Independence Valley Dr., Grand Junction, CO 81507.

11 

### Mitchell Method M5331, Revision 1.1. “Determination of Turbidity by LED Nephelometry,” March 5, 2009. Available at http://www.nemi.gov or from Leck Mitchell, PhD, PE, 656 Independence Valley Dr., Grand Junction, CO 81507.

12 

### Orion Method AQ4500, Revision 1.0. “Determination of Turbidity by LED Nephelometry,” May 8, 2009. Available at http://www.nemi.gov or from Thermo Scientific, 166 Cummings Center, Beverly, MA 01915, http://www.thermo.com

.

13 

### Modified Colitag TM 

### Method, “Modified Colitag TM 

### Test Method for the Simultaneous Detection of E. coli and other Total Coliforms in Water (ATP D05–0035),” August 28, 2009. Available at http://www.nemi.gov or from CPI, International, 580 Skylane Boulevard, Santa Rosa, CA 95403.

14 

### EPA Method 557. “Determination of Haloacetic Acids, Bromate, and Dalapon in Drinking Water by Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC–ESI– MS/MS),” September 2009. EPA 815–B–09–012. Available at http://water.epa.gov/scitech/drinkingwater/labcert/analyticalmethods_expedited.cfm.

15 

### AMI Turbiwell, “Continuous Measurement of Turbidity Using a SWAN AMI Turbiwell Turbidimeter,” August 2009. Available at http://www.nemi.gov or from Markus Bernasconi, SWAN Analytische Instrumente AG, Studbachstrasse 13, CH–8340 Hinwil, Switzerland.

16 

### EPA Method 334.0. “Determination of Residual Chlorine in Drinking Water Using an On-line Chlorine Analyzer,” August 2009. EPA 815–B–09–013. Available at http://epa.gov/safewater/methods/analyticalmethods_ogwdw.html

.

17 

### ChloroSense. “Measurement of Free and Total Chlorine in Drinking Water by Palintest ChloroSense,” September 2009. Available at http://www.nemi.gov or from Palintest Ltd, 21 Kenton Lands Road, PO Box 18395, Erlanger, KY 41018.

18 

### EPA Method 302.0. “Determination of Bromate in Drinking Waters using Two-Dimensional 

## inductively coupled plasma-atomic emission spectrometry (AVICP–AES) Revision 4.2

Atomic Absorption; Direct Aspiration 3111 B
Inductively Coupled Plasma 3120 B 

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...

### Ion Chromatography with Suppressed Conductivity Detection,” September 2009. EPA 815–B– 09–014. Available at http://epa.gov/safewater/methods/analyticalmethods_ogwdw.html

.

19 

### EPA 415.3, Revision 1.2. “Determination of Total Organic Carbon and Specific UV A bsorbance at 254 nm in Source Water and Drinking Water,” August 2009. EPA/600/R– 09/122. Available at http://www.epa.gov/nerlcwww/ordmeth.htm.

20 

### Readycult® 

### Method, “Readycult® 

### Coliforms 100 Presence/Absence Test for Detection and Identification of Coliform Bacteria and Escherichia coli in Finished Waters,” January, 2007. Version 1.1. Available from EMD Chemicals (affiliate of Merck KGaA, Darmstadt, Germany), 480 S. Democrat Road, Gibbstown, NJ 08027–1297.

21 

### Chromocult® 

### Method, “Chromocult® 

### Coliform Agar Presence/Absence Membrane Filter Test Method for Detection and Identification of Coliform Bacteria and Escherichia coli in Finished Waters,” November, 2000. Version 1.0. EMD Chemicals (affiliate of Merck KGaA, Darmstadt, Germany), 480 S. Democrat Road, Gibbstown, NJ 08027–1297.

22 

### Hach Company Method, “Hach Company SPADNS 2 (Arsenic-free) Fluoride Method 10225—Spectrophotometric Measurement of Fluoride in Water and Wastewater,” January 2011. 5600 Lindbergh Drive, P.O. Box 389, Loveland, Colorado 80539. (Available at http://www.hach.com. )

23 

### Hach Company Method, “Hach Company TNTplus TM 

### 835/836 Nitrate Method 10206— Spectrophotometric Measurement of Nitrate in Water and Wastewater,” January 2011. 5600 Lindbergh Drive, P.O. Box 389, Loveland, Colorado 80539. (Available at http://www.hach.com. )

[74 FR 38353, Aug. 3, 2009, as amended at 74 FR 57914, Nov. 10, 2009; 74 FR 63069, Dec. 2, 2009; 75 FR 32299, June 8, 2010; 76 FR 37018, June 24, 2011]


### Subpart D—Reporting and Recordkeeping

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### § 141.31 Reporting requirements.

top
(a) Except where a shorter period is specified in this part, the supplier of water shall report to the State the results of any test measurement or analysis requ ired by this part within (1) The first ten days following the month in which the result is receive d, or (2) the first ten days following the end of the required monitoring period as stipulated bythe State, whichever of these is shortest.
(b) Except where a different reporting pe riod is specified in this part, the supplier of water must report to the State within 48 hours the failure to comply with any national primary drinking water regulation (including failure to comply with monitorin g requirements) set forth in this part.
(c) The supplier of water is not required to report analytical results to the State in cases where a State laboratory performs the analysis and reports the result s to the State office which would normally receive such notification from the supplier.

(d) The public water system, within 10 days of completing the public notification requirements under Subpart Q of this part for the initial public notice and any repeat notices, must submit to the primacy agency a certification that it has fully complied with the public notification regulations. The public water system must include with this certification a re presentative copy of each type of notice distributed, published, posted, and made available to the persons served by the system and to the media.
(e) The water supply system shall submit to the State within the time stated in the request copies of any records required to be maintained under §141.33 hereof or copies of any documents then in existence which the State or the Administrator is entitled to in spect pursuant to the authority of section 1445 of the Safe Drinking Water Act or the equi valent provisions of State law.

[40 FR 59570, Dec. 24, 1975, as amended at 45 FR 57345, Aug. 27, 1980; 65 FR 26022, May 4, 2000]


### § 141.32 [Reserved]

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### § 141.33 Record maintenance.

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A ny owner or operator of a public water system subject to the provisions of this part shall retain on its premises or at a convenient location nearits premises the following records:
(a) Records of microbiological analyses and turbidityanalyses made pursuant to this part shall be kept for not less than 5 years. Records of chemical analyses made pursuant to this part shall be kept for not less than 10 years. Actual laboratory reports may be kept, or data may be transferred to tabular summaries, provided that the follo wing information is included:
(1) The date, place, and time of sampling, and the name of the person who collected the sample;
(2) Identification of the sample as to whether it wa s a routine distribution system sample, check sample, raw or process water sample or other special purpose sample;
(3) Date of analysis; 

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...(4) Laboratory and person respons ible for performing analysis;
(5) The analytical technique/method used; and
(6) The results of the analysis.
(b) Records of action taken by the sys tem to correct violations of primary drinking water regulations shall be kept for a period not less than 3 years after the la st action taken with res pect to the particular violation involved.
(c) Copies of any written reports, summaries or communications relating to sanitary surveys of the system conducted by the system itself, by a private co nsultant, or by any local, State or Federal agency, shall be kept for a period not less than 10 years after completion of the sanitary survey involved.

(d) Records concerning a variance or exemption granted to the system shall be kept for a period ending not less than 5 years following the expiration of such variance or exemption.
(e) Copies of public notices issued pursuant to Subpart Q of this part and certifications made to the primacy agency pursuant to §141.31 must be kept for three years after issuance.
(f) Copies of monitoring plans deve loped pursuant to this part shall be kept for the same period of time as the records of analyses taken under the plan are required to be kept under paragraph (a) of this section, except as specified elsewhere in this part.

[40 FR 59570, Dec. 24, 1975, as amended at 65 FR 26022, May 4, 2000; 71 FR 478, Jan. 4, 2006]


### § 141.34 [Reserved]

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### § 141.35 Reporting for unregulated contaminant monitoring results.

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(a) General applicability. This section applies to any owner or operator of a public water system (PWS) required to monitor for unregulated contaminants under §141.40(a); such owner or operator is referred to as “you.” This section specifies the information that must be reported to EPA prior to the commencement of monitoring and describes the process for reporting monitoring results to EPA. For the purposes of this section, PWS “popul ation served” includes the sum of the retail population served directly by the PWS plus the population served by anyconsecutive system(s) rece iving all or part of its finished water from that PWS. For purposes of thi s section, the term “finished” means water that is introduced into the distribution system of a PWS and is intended for distribution and consumption without further treatment, except the treatment necessary to main tain water quality in the distribution system (e.g., booster disinfection, addition of corrosion control chemicals). For pu rposes of this section, the term “State” refers to the State or Tribal government enti ty that has jurisdiction over your PWS even if that government does not have primary enforcement respons ibility for PWSs under the Safe Drinking Water A ct. For purposes of this section, the term “PWS Offici al” refers to the person at your PWS who is able to function as the official spokesperson for the system' s Unregulated Contaminant Monitoring Regulation (UCMR) activities; and the term “P WS Technical Contact” refers to the person at your PWS who is responsible for the technica l aspects of your UCMR activities, such as details concerning sampling and reporting.
(b) Reporting by all systems . You must meet the reporting requirements of this paragraph if you meet the applicability criteria in §141.40(a)(2).
(1) Where to submit UCMR reporting requirement information . Some of your reporting requirements are to be fulfilled electronically, and others by mail . Information that must be submitted using EPA's electronic data reporting system must be submitted through: http://www.epa.gov/safewater/ucmr/ucmr2/reporting.html . Documentation that is required to be mailed can be submitted either: To UCMR Sampling Coordinator, USEPA, Technical Support Center, 26 West Martin Luther King Drive (MS 140), Cinc innati, OH 45268; or by e-mail at UCMR_Sampling_Coordinator@epa.gov ; or by fax at (513) 569–7191. In addition, you must notify the public of the availability of unregulated contamina nt monitoring data as provided in Subpart Q (Public Notification) of this part (40 CFR 141.207). Co mmunity Water Systems that detect unregulated contaminants under this monitoring must also addr ess such detections as part of their Consumer Confidence Reports, as provided in Subpart O of this part (40 CFR 141.151).

(2) Contacting EPA if your system does not meet applic ability criteria or has a status change. If you have received a letter from EPA concerning your requir ed monitoring and your system does not meet the applicability criteria for UCMR established in §141.40(a)(2), or if a change occurs at your system that may affect your requirements under UCMR as defined in §141.40(a)(3) through (5), you must fax, mail, or e-mail a letter to EPA, as specified in paragraph (b)(1) of this section. The letter must be from your PWS Official and must include an explanation as to why the UCMR requirements are not applicable to your PWS, or have changed for your PWS, along with the appropriate contact information. EPA will make an applicability determination based on your letter and in cons ultation with the State when necessary. You are subject to UCMR requirements unless and until you receive a letter from EPA agreeing that you do not meet the applicability criteria.
(c) Reporting by large systems . If you serve a population of more than 10,000 people, and meet the applicability criteria in §141.40(a)(2)(i), you must meet the reporting requirements in paragraphs (c)(1) through (8) of this section.
(1) Contact information . You must provide contact informati on by April 4, 2007, and provide updates within 30 days if this information changes. Th e contact information must be submitted using EPA's electronic data reporting system, as specified in pa ragraph (b)(1) of this section, and include the name, affiliation, mailing address, phone number, fax numb er, and e-mail address for your PWS Technical Contact and your PWS Official.
(2) Sampling location and inventory information. You must provide your samp ling location and inventory information by August 2, 2007 using EPA's electron ic data reporting system. You must submit the following information for each sampling location, orfor each approved representative sampling location (as specified in paragraph (c)(3) of this section re garding representative sa mpling locations): PWS identification (PWSID) code; PW S facility identification code; w ater source type, sampling point identification code; and sampling point type code; ( as defined in Table 1, paragraph (e) of this section). 

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...If this information changes, you mustreport updates to EPA's electronicdata reporting system within 30 days of the change.

(3) Proposed ground water representative sampling locations . Some systems that use ground water as a source and have multiple entry points to the distri bution system (EPTDSs) may propose monitoring at representative entry point(s), rather than monitor at every EPTDS, as follows:
(i) Qualifications . Large PWSs that have EPA- or State-approv ed alternate EPTDS sampling locations from a previous UCMR cycle, or as provided for under §§141.23(a)(1), 141.24(f)(1), or 141.24(h)(1), may submit a copy of documentation from their State or EPA that approves their alternative sampling plan for EPTDSs. PWSs that do not have an approved alternative EPTDS sampling plan may submit a proposal to sample at representative EPTDS(s) rather than at ea ch individual EPTDS if: They use ground water as a source; all of their well sources have either the same treatment or no treatment; and they have multiple EPTDSs from the same source, such as an aq uifer. You must submit a copy of the existing alternate EPTDS sampling plan or your representative well proposal, as appropriate, by May 4, 2007, as specified in paragraph (b)(1) of this section.

(ii) Demonstration. If you are submitting a propos al to sample at representative EPTDS(s) rather than at each individual EPTDS, you must demonstrate that any EPTDS that you select as representative of the ground water you supply from multiple wells is associated with a well that draws from the same aquifer as the wells it will represent. You must submit the following information for each proposed representative sampling location: PWSID Code, PWS Facility Identi fication Code, and Sampling Point Identification Code (as defined in Table 1, paragraph (e) of this section). You must also include documentation to support your proposal that the specified wells are re presentative of other wells. This documentation can include system-maintained well logs or construction drawings indicati ng that the representative well(s) is/are at a representative depth, and details of well casings and grouting; data demonstrating relative homogeneity of water quality constituents (e.g., pH, dissolved oxygen, conductivity, iron, manganese) in samples drawn from each well; and data showing that your wells are located in a limited geographic area (e.g., all wells within a 0.5 mile radius) and/or , if available, the hydrogeol ogic data indicating the time of travel separating the representative well from each of the individual wells it represents (e.g., all wells within a five-year time of travel delineation). Your proposal must be sent in writing to EPA, as specified in paragraph (b)(1) of this section. You must also provide a copy of this information to the State, unless otherwise directed by the State. Informa tion about the actual or potential occurrence or non-occurrence of contaminants in an individual well, or a well's vulnerability to contamination, must not be used as a basis for sele cting a representative well.
(iii) Approval . EPA or the State (as specified in the Partnership Agreement reached between the State and EPA) will review your proposal, coordinate any ne cessary changes with you, and approve the final list of EPTDSs where you will be required to monitor. Y our plan will not be final until you receive written approval from EPA or the State.

(4) Contacting EPA if your PWS has not been notified of requirements. If you believe you are subject to UCMR requirements, as defined in §141.40(a)(1) and (2)(i), and you have not been notified by either EPA or your State by June 4, 2007, you must send a letter to EPA, as specif ied in paragraph (b)(1) of this section. The letter must be from your PWS O fficial and must include an explanation as to why the UCMR requirements are applicable to your system along with the appropriate contact information. A copy of the letter must also be submitted to the S tate, as directed by the State. EPA will make an applicability determination based on your letter, an d in consultation with the State when necessary, and will notify you regarding your applicability status a nd required sampling schedule. However, if your PWS meets the applicability criteria sp ecified in §141.40(a)(2)(i), you ar e subject to the UCMR monitoring and reporting requirements, regardless of whether you have been notified by the State or EPA.
(5) Notifying EPA if your PWS cannot sample according to schedule

. (i) General rescheduling notification requirements . Large systems may change their Assessment Monitoring (List 1) or Screening Survey (List 2) schedule up to August 2, 2007 using EPA's electronic data reporting system, as specified in paragraph (b)(1) of this section. After these dates have passed, if your PWS cannot sample according to your as signed sampling schedule (e.g., because of budget constraints, or if a sampling location will be clos ed during the scheduled month of monitoring), you must fax, mail, or e-mail a letter to EPA, as specified in pa ragraph (b)(1) of this section, prior to the scheduled sampling date. You must include an explanati on of why the samples cannot be taken according to the assigned schedule and the alternative schedule you are requesting. You are subject to your assigned UCMR sampling schedule or the schedule that you revi sed on or before August 2, 2007, unless and until you receive a letter from EPA specifying a new schedule.
(ii) Exceptions to the rescheduling notification requirements . For ground water sampling, if the second round of sampling will be completed five to seven months after the first sampling event, as specified in Table 2 of §141.40(a)(4)(i)(B), no notification to EPA is required. If any ground water sampling location will be non-operational for more than one month before and one month after the month in which the second sampling event is scheduled ( i.e. , it is not possible for you to sample within the five to seven month window), you must notify EPA, as specified in paragraph (b)(1) of this section, explaining why the schedule cannot be met. You must comply wi th any modified schedule provided by EPA.
(6) Reporting monitoring results . For each sample, you must report th e information specified in Table 1 of paragraph (e) of this section, usin g EPA's electronic data reporting system, as follows. If you are conducting Assessment Monitoring, you must incl ude data elements 1 through 5, and 7 through 15 in paragraph (e) of this section; and if you are conduc ting Screening Survey monitoring, you must include elements 1 through 15. You also must report any changes made to data elements 1 through 6 to EPA, in writing, explaining the nature and purpose of the propos ed change, as specified in paragraph (b)(1) of this section.
(i) Electronic reporting system . You are responsible for ensuring that the laboratory conducting the analysis of your unregulated contaminant monitoring samples (your laboratory) posts the analytical results to EPA's electronic reporting system. You are also responsible for reviewing, approving, and submitting those results to EPA.
(ii) Reporting schedule . You must ensure that your laboratoryposts the data to EPA's electronic data reporting system within 120 days from the sample collection date (sample co llection must occur as specified in §141.40(a)(4)). You have 60 days from when the laboratory posts the data in EPA's electronic data reporting system to review, approve, and submit the data to the State and EPA, at the Web address specified in paragraph (b)(1) of this sect ion. If you do not take action on the data within 60 days of the laboratory's posting to the electronic reporting system, the data will be considered approved by you, and available for EPA and State review.
(7) Only one set of results accepted . If you report more than one set of valid results for the same sampling location and the same sampling event (forexample, because you have had more than one laboratory analyze replicate samples collected under §141.40(a)(5), or because you have collected multiple samples during a single monitoring event at the same sampling location), EPA will use the 

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...highest of the reported values as the official result.
(8) No reporting of previously collected data . You cannot report previously collected data to meet the testing and reporting requirements for the contamin ants listed in §141.40(a)(3). All analyses must be performed by laboratories approved by EPA to perform UCMR analyses using th e analytical methods specified in Table 1 of §141.40(a)(3) and using samples collected according to §141.40(a)(4). Such requirements preclude the possibility of “grandfathering” previously collected data.
(d) Reporting by small systems. If you serve a population of 10,000 or fewer people, and you are notified that you have been selected for UCMR monitoring, yourreporting requirements will be specified within the materials that EPA sends you, including a request for contact information, and a request for information associated with the sampling kit.
(1) Contact information. EPA will send you a notice requesting contact information for key individuals at your system, including name, affiliation, mailing address, phone number, fax number, and e-mail address. These individuals include your PWS Tech nical Contact and your PWS Official. You are required to provide this information within 90 days of receiving the notice from EPA as specified in paragraph (b)(1) of this section. If this informati on changes, you also must provide updates within 30 days of the change, as specified in paragraph (b)(1) of this section.
(2) Reporting sampling information. You must record data elements listed in Table 1 of paragraph (e) of this section on each sample form and sample bottle provided to you by the UCMR Sampling Coordinator, as follows: If you are conducting As sessment Monitoring, you must include elements 1 through 5, and 7; if you are conducting Screening Survey, you must include elements 1 through 7. You must send this information as specified in the instruct ions of your sampling kit, which will include the due date and return address. You must report any changes made in data elements 1 through 6 by mailing or e-mailing an explanation of the nature and purpos e of the proposed change to EPA, as specified in paragraph (b)(1) of this section.

(e) Data elements. Table 1 defines the data elements that must be provided with UCMR sample results.
Table 1—Unregulated Contaminant Monitoring Reporting Requirements



## Data element Definition 1. Public Water System Identification (PWSID) Code The code used to identify each PWS. The code begins with the standard 2-character postal State abbreviation or Region code; the remaining 7 numbers are unique to each PWS in the State. The same identification code must be used to represent the PWS identification for all current and future UCMR monitoring. 2. Public Water System Facility Identification Code An identification code established by the State or, at the State's discretion, by the PWS, following the format of a 5- digit number unique within each PWS for each applicable facility ( i.e. , for each source of water, treatment plant, distribution system, or any ot her facility associated with water treatment or delivery). The same identification code must be used to represent the facility for all current and future UCMR monitoring. 3. Water Source Type The type of source water that supplies a water system facility. Systems must report one of the following codes for each sampling location: SW = surface water (to be reported for water facilities that are served all or in part by a surface water source at any time during the twelve-month period). GW = ground water (to be reported for water facilities that are served entirely by a ground water source). GU = ground water under the direct influence of surface water (to be reported for water facilities that are served all or in part by ground water under the direct influence of surface water at any time during the twelve-month sampling period), and are not served at all by surface water during this period. 4. Sampling Point Identification Code An identification code established by the State, or at the State's discretion, by the PWS, that uniquely identifies each sampling point. Each sampling code must be unique within each applicable facility, fo r each applicable sampling location ( i.e. , entry point to the distribution system or distribution system sample at maximum residence time). The same identification code must be used to represent the sampling location for all current and future UCMR monitoring. 5. Sampling Point Type Code A code that identifies the location of the sampling point as either: EP = entry point to the distribution system. MR = distribution system sample at maximum residence time. 6. Disinfectant Residual Type The type of disinfectant in use at the time of UCMR sampling to maintain a residual in the distribution system for each Screening Survey sampling point. To be reported by systems required to conduct Screening Survey monitoring. 

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...[72 FR 389, Jan. 4, 2007]


### Subpart E—Special Regulations, Including Monitoring Regulations and Prohibition on Lead Use

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### § 141.40 Monitoring requirements for unregulated contaminants.

top 

## Systems must report using the following codes for each Screening Survey sampling location ( i.e. , EP, MR): CL = chlorine CA = chloramine OT = all other types of disinfectant (e.g., chlorine dioxide) ND = no disinfectant used. 7. Sample Collection Date The date the sample is collected, reported as 4-digit year, 2-digit month, and 2-digit day. 8. Sample Identification Code An alphanumeric value up to 30 characters assigned by the laboratory to uniquely identify containers, or groups of containers, containing water samples collected at the same sampling location for the same sampling date. 9. Contaminant The unregulated contaminant for which the sample is being analyzed. 10. Analytical Method Code The identification code of the analytical method used.
11. Sample Analysis Type The type of sample collected and/or prepared, as well as the fortification level. Permitted values include: FS = field sample; sample collected and submitted for analysis under this rule. LFSM = laboratory fortified sample matrix; a UCMR field sample with a known amount of the contaminant of interest added. LFSMD = laboratory fortified sample matrix duplicate; duplicate of the laboratory fortified sample matrix. CF = concentration fortified; reported with sample analysis types LFSM and LFSMD, the concentration of a known contaminant added to a field sample. 12. Analytical Results—Sign A value indicating whether the sample analysis result was:
(<) “less than” means the contaminant was not detected, or was detected at a level below the Minimum Reporting Level. (=) “equal to” means the contaminant was detected at the level reported in “Ana lytical Result—Value.” 13. Analytical Result—Value The actual numeric value of the analytical results for: field samples; laboratory fortifie d matrix samples; laboratory fortified sample matrix duplicates; and concentration fortified. 14. Laboratory Identification Code The code, assigned by EPA, used to identify eachlaboratory. The code begins with the standard twocharacter State postal abbreviation; the remaining five numbers are unique to each laboratory in the State. 15. Sample Event Code A code assigned by the PWS for each sample event. This will associate samples with t he PWS monitoring plan to allow EPA to track compliance and completeness. Systems must assign the following codes: SE1 = represents samples collected to meet the UCMR monitoring requirement for the first sampling period (all source types). SE2 = represents samples collected to meet the UCMR monitoring requirement for the second sampling period (all source types). SE3 = represents samples collected to meet the UCMR monitoring requirement for the third sampling period (surface water and ground water under the direct influence of surface water (GWUDI) sources only). SE4 = represents samples collected to meet the UCMR monitoring requirement for the fourth sampling period (surface water and GWUDI sources only). 

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...(a) General applicability. This section specifies the monitoring an d quality control requirements that must be followed if you own or operate a public water system (PWS) that is subject to the Unregulated Contaminant Monitoring Regulation (UCMR), as specif ied in paragraphs (a)(1) and (2) of this section. In addition, this section specifies the UCMR requir ements for State and Tribal participation. For the purposes of this section, PWS “popul ation served,” “State,” “ PWS Offi cial,” “PWS Technical Contact,” and “finished water” apply as defined in §141.35(a) . The determination of whether a PWS is required tomonitor under this rule is based on the type of system (e.g., community water system, non-transient noncommunity water system, etc.); whether the system purc hases all of its water, as finished water, from another system; and its population served as of June 30, 2005.
(1) Applicability to transient non-community systems. If you own or operate a transient non-community water system, you do not have to monitor that system for unregulated contaminants.
(2) Applicability to community water systems an d non-transient non-community water systems.
(i) Large systems. If you own or operate a wholesale or retail PWS (other than a transient noncommunity system) that serves more than 10,000 people, and do not purchase your entire water supply as finished water from another PWS, you must monito r according to the specifications in this paragraph (a)(2)(i). If you believe that your applicability status is different than EPA has specified in the notification letter that you received, or if you are subject to UC MR requirements and you have not been notified by either EPA or your State, you must report to EPA, as specified in §141.35(b)(2) or (c)(4).

(A) Assessment Monitoring. You must monitor for the unregulated contaminants on List 1 of Table 1, UCMR Contaminant List, in paragraph (a)(3) of this section. If you serve a population of more than 10,000 people, you are required to perform this monitoring regardless of whether you have been notified by the State or EPA.
(B) Screening Survey. You must monitor for the unregulated cont aminants on List 2 (Screening Survey) of Table 1, as specified in paragraph (a)(3) of this section, if your system serves 10,001 to 100,000 people and you are notified by EPA or your State t hat you are part of the State Monitoring Plan for Screening Survey testing. If your system serves more than 100,000 people, you are required to conduct this Screening Survey testing regardless of whether y ou have been notified by the State or EPA.
(C) Pre-Screen Testing. You must monitor for the unregulated c ontaminants on List 3 of Table 1, in paragraph (a)(3) of this section, if notified by your State or EPA that you are part of the Pre-Screen Testing.
(ii) Small systems. Small PWSs, as defined in this paragraph, will not be selected to monitor for any more than one of the three monitoring lists provided in Table 1, UCMR Contaminant List, in paragraph (a)(3) of this section. EPA will provide sample conta iners, provide pre-paid air bills for shipping the sampling materials, conduct the laboratory analysis , and report and review monitoring results for all small systems selected to conduct monitoring under paragraphs (a)(2)(ii)(A) through (C) of this section. If you own or operate a PWS (other than a transient system) that serves 10,000 or fewer people and do not purchase your entire water supply from another PWS, you must monitor as follows:
(A) Assessment Monitoring. You must monitor for the unregulated c ontaminants on List 1 of Table 1, in paragraph (a)(3) of this section, if you are notified by your State or EPA that you are part of the State Monitoring Plan for Assessment Monitoring.
(B) Screening Survey. You must monitor for the unregulated cont aminants on List 2 of Table 1, in paragraph (a)(3) of this section, if notified by your State or EPA that you are part of the State Monitoring Plan for the Screening Survey.
(C) Pre-Screen Testing. You must monitor for the unregulated c ontaminants on List 3 of Table 1, in paragraph (a)(3) of this section, if you are notified by your State or EPA that you are part of the State Monitoring plan for Pre-Screen Testing.
(3) Analytes to be monitored. Lists 1, 2, and 3 of unregulated contaminants are provided in the following table:

Table 1—UCMR Contaminant List

[List 1: Assessment Monito ring Chemical Contaminants]



## 1—Contaminant 2—CAS registry number 3— Analytical methods a 

## 4— Minimum reporting

level b 

## 5— Sampling location c 

## 6—Period during which monitoring to be completed Dimethoate 60–51–5 EPA 527 d 

## 0.7 μ g/L EPTDS 1/1/2008– 12/31/2010 Terbufos sulfone 56070– 16–7 EPA 527 d 

## 0.4 μ g/L EPTDS 1/1/2008– 12/31/2010 2,2',4,4'- tetrabromodiphenyl ether (BDE–47) 5436– 43–1 EPA 527 d 

## 0.3 μ g/L EPTDS 1/1/2008– 12/31/2010
2,2',4,4',5- pentabromodiphenyl ether (BDE–99) 60348– 60–9 EPA 527 d 

## 0.9 μ g/L EPTDS 1/1/2008– 12/31/2010
2,2',4,4',5,5'- hexabromobiphenyl (HBB) 59080– 40–9 EPA 527 d 

## 0.7 μ g/L EPTDS 1/1/2008– 12/31/2010
2,2',4,4',5,5'- hexabromodiphenyl ether (BDE–153) 68631– 49–2 EPA 527 d 

## 0.8 μ g/L EPTDS 1/1/2008– 12/31/2010
2,2',4,4',6- 189084– 0.5 μ g/L EPTDS 1/1/2008– 

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...Table 1—UCMR Contaminant List

[List 2: Screening Survey Chemical Contaminants

Table 1—UCMR Contaminant List

[List 3: Pre-Screen Testing to be Sampled After Notice of Analytical Methods Availability] 

## pentabromodiphenyl ether (BDE–100) 64–8 EPA 527 d 

## 12/31/2010
1,3-dinitrobenzene 99–65–0 EPA 529 e 

## 0.8 μ g/L EPTDS 1/1/2008– 12/31/2010 2,4,6-trinitrotoluene (TNT) 118–96– 7 EPA 529 e 

## 0.8 μ g/L EPTDS 1/1/2008– 12/31/2010 Hexahydro-1,3,5- trinitro-1,3,5-triazine (RDX) 121–82– 4 EPA 529 e 

## 1 μ g/L EPTDS 1/1/2008– 12/31/2010

1—Contaminant 2—CAS registry number 3— Analytical methods a 

## 4— Minimum reporting

level b 

## 5— Sampling location c 

## 6—Period during which monitoring to be completed Acetanilide Pesticide Degradation Products Acetochlor ESA 187022– 11–3 EPA 535 f 

## 1 μ g/L EPTDS 1/1/2008– 12/31/2010 Acetochlor OA 184992– 44–4 EPA 535 f 

## 2 μ g/L EPTDS 1/1/2008– 12/31/2010 Alachlor ESA 142363– 53–9 EPA 535 f 

## 1 μ g/L EPTDS 1/1/2008– 12/31/2010 Alachlor OA 171262– 17–2 EPA 535 f 

## 2 μ g/L EPTDS 1/1/2008– 12/31/2010 Metolachlor ESA 171118– 09–5 EPA 535 f 

## 1 μ g/L EPTDS 1/1/2008– 12/31/2010 Metolachlor OA 152019– 73–3 EPA 535 f 

## 2 μ g/L EPTDS 1/1/2008– 12/31/2010 Acetanilide Pesticide Parent Compounds Acetochlor 34256– 82–1 EPA 525.2 g 

## 2 μ g/L EPTDS 1/1/2008– 12/31/2010 Alachlor 15972– 60–8 EPA 525.2 g 

## 2 μ g/L EPTDS 1/1/2008– 12/31/2010 Metolachlor 51218– 45–2 EPA 525.2 g 

## 1 μ g/L EPTDS 1/1/2008– 12/31/2010 NitrosaminesNnitrosodiethylamine (NDEA) 55–18–5 EPA 521 h 

## 0.005 μ g/L DSMRT and EPTDS 1/1/2008– 12/31/2010

N-nitrosodimethylamine (NDMA) 62–75–9 EPA 521 h 

## 0.002 μ g/L DSMRT and EPTDS 1/1/2008– 12/31/2010

N-nitroso-di-nbutylamine (NDBA) 924–16– 3 EPA 521 h 

## 0.004 μ g/L DSMRT and EPTDS 1/1/2008– 12/31/2010

N-nitroso-di-npropylamine (NDPA) 621–64– 7 EPA 521 h 

## 0.007 μ g/L DSMRT and EPTDS 1/1/2008– 12/31/2010

N-nitrosomethylethylamine (NMEA) 10595– 95–6 EPA 521 h 

## 0.003 μ g/L DSMRT and EPTDS 1/1/2008– 12/31/2010
N-nitrosopyrrolidine (NPYR) 930–55– 2 EPA 521 h 

## 0.002 μ g/L DSMRT and EPTDS 1/1/2008– 12/31/2010

1— Contaminant 2—CAS registry number 3— Analytical methods a 

## 4— Minimum reporting

level b 

## 5— Sampling location c 

## 6—Period during which monitoring to be completed Reserved i 

## Reserved i 

## Reserved i 

## Reserved i 

## Reserved i 

## Reserved i 

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...Column headings are:
1—Contaminant: The name of the contaminant to be analyzed.
2—CAS (Chemical Abstract Service) Registry Nu mber or Identification Number: A unique number identifying the chemical contaminants.
3—Analytical Methods: method numbers identify ing the methods that must be used to test the contaminants.
4—Minimum Reporting Level: The value and unit of measure at or above which the concentration of the contaminant must be measured using the approved analytical methods.
5—Sampling Location: The locations within a PWS at which samples must be collected.
6—Period During Which Monitoring To Be Completed: The dates during which the sampling and testing are to occur for the indicated contaminant.
The analytical procedures shall be performed in ac cordance with the documents associated with each method (per the following footnotes). The incorporation by reference of the following documents listed in footnotes d—h was approved by the Director of the F ederal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Information on how to obtain these documents can be provided by the Safe Drinking Water Hotline at (800) 426–4791. Documents may be inspected at EPA's Drinking Water Docket, 1301 Constitution Avenue, NW., EPA West, Room B 102, Washington, DC 20460, Telephone: (202) 566– 2426; or at the National Archives and Records Administ ration (NARA). For inform ation on availability of this material at NARA, call 202–741–6030, or go to: http://www.archives.gov/federal-register/index.html.

a The version of the EPA methods which you must follow for this Regulation are listed in d—h as follows.

b The Minimum Reporting Level (MRL) was established by EPA by adding the mean of the Lowest Concentration Minimum Reporting Levels (LCMRL) determined accordi ng to the procedure detailed in “Statistical Protocol for the Determination of The Single-Laboratory Lowest Concentration Minimum Reporting Level (LCMRL) and Validation of the Mi nimum Reporting Level (MRL)” by the primary and secondary laboratories conducting the developmentand validation of the analytical method to three times the difference of the LCMRLs. If LCMRL data from three or more laboratories were available, the MRL was established by EPA by adding three times the standard deviation of the LCMRLs to the mean of the LCMRLs. Note that EPA Method 525.2 was developed prior to UCMR 2, hence the LCMRLs were not determined for analytes determined by this method.

c Sampling must occur at entry points to the distribution system (EPTDSs) after treatment is applied that represent each non-emergency water source in routine use over the 12-month period of monitoring. See 40 CFR 141.35(c)(3) for an explanation of the requ irements related to use of representative EPTDSs. Sampling for nitrosamines on List 2 must also occu r at the disinfection byproduc t distribution system maximum residence time (DSMRT) sampling locations as defined in 40 CFR 141.132(b)(1)(i) and at EPTDS sampling locations. If a treatment plant/water source is not subject to the sampling required in 40 CFR 141.132(b)(1), then the samples for nitrosamines must be collected only at the EPTDS location (s).

d EPA Method 527 “Determination of Selected Pesticides and Flame Retardants in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass S pectrometry (GC/MS),” Revision 1.0, April 2005 is available at http://www.epa.gov/safewater /methods/sourcalt.html.

e EPA Method 529 “Determination of Expl osives and Related Compounds in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chro matography/Mass Spectrometry (GC/MS),” Revision 1.0, September 2002 is available at http://www.epa.gov/nerlcwww/ordmeth.htm.

f EPA Method 535 “ Measurement of Chloroacetanilide and Other Acetamide Herbicide Degradates in Drinking Water by Solid Phase Extraction and Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS),” Version 1.1, April 2005 is available at http://www.epa.gov/nerlcwww/ordmeth.htm.

g EPA Method 525.2 “Determination of Organic Compounds in Drinking Water by Liquid-Solid Extraction and Capillary Column Gas Chromatography/Mass Sp ectrometry,” Revision 2.0, 1995 is available at http://www.NEMI.gov.

h EPA Method 521 “Determination of Nitros amines in Drinking Water bySolid Phase Extraction and Capillary Column Gas Chromatography with Large Volume Injection and Chemical Ionization Tandem Mass Spectrometry (MS/MS),” Version 1.0, September 2004 is available at http://www.epa.gov/nerlcwww/ordmeth.htm.

i To be determined at a later time.
(4) Sampling requirements —(i) Large systems. If you serve more than 10,000 people and meet the UCMR applicability criteria specified in paragraph (a )(2)(i) of this section, you must comply with the requirements specified in paragraphs (a)(4)(i)(A) through (I) of this section. Your samples must be collected according to the schedule that you are assi gned by EPA or your State, or the schedule that you revised using EPA's electronic data reporting system on or before August 2, 2007. Your schedule must follow both the timing and frequency of monitoring specified in Tables 1 and 2 of this section.

(A) Monitoring period. You must collect the samples in one continuous 12-month period for List 1 Assessment Monitoring, and, if applicable, for List 2 Screening Survey, or List 3 Pre-Screen Testing, during the time frame indicated in column 6 of Tabl e 1, in paragraph (a)(3) of this section. EPA or your State will specify the month(s) and year(s) in which your monitoring must occur. As specified in §141.35 (c)(5), you must contact EPA if you believe you c annot conduct monitoring according to your schedule.
(B) Frequency. You must collect the samples within the time frame and according to the frequency specified by contaminant type and water source type fo r each sampling location, as specified in Table 2, in this paragraph, with the following exception. For the second round of ground water sampling, if a sample location is non-operational for more than one month before and one month after the scheduled sampling month ( i.e. , it is not possible for you to sample within the five to seven month window specified the Table 2, in this paragraph), you must notify EPA as specified in §141.35(c)(5).

Table 2—Monitoring Frequency by Contaminant and Water Source Types 

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...(C) Location. You must collect samples for each List 1 Assessment Monitoring contaminant, and, if applicable, for each List 2 Screening Survey, or List 3 Pre-Screen Testi ng contaminant, as specified in Table 1, in paragraph (a)(3) of this section. Samples must be collected at each sample point that is specified in column 5 of Table 1, in paragraph (a)(3) of this section. If you are a ground water system with multiple EPTDSs, and you request and receive approval from EPA or the State for sampling at representative EPTDS(s), as specified in §141.35( c)(3), you must collect your samples from the approved representative sampling loc ation(s). Systems conducting Scre ening Survey monitoring must also sample for nitrosamines at the disinfection by product distribution system maximum residence time (DSMRT) sampling location(s) if they are subject to sampling requirements in §141.132(b)(1).

(D) Sampling instructions. For each List 1 Assessment Monitoring contaminant, and, if applicable, for each List 2 Screening Survey, or List 3 Pre-Screen Testing contaminant, you must follow the sampling procedure for the method specified in column 3 of Table 1, in paragraph (a)(3) of this section. In addition, you must not composite (t hat is, combine, mix, or blend) the samples; you must collect and preserve each sample separately. Samples collected for the analysis of Acetanilide “parent” pesticides and their degradation products (Methods 525.2 and 5 35) must be collected at the same sampling point, at the same time.
(E) Sample collection and shipping time. If you must ship the samples for analysis, you must collect the samples early enough in the day to allow adequate time to send the samples for overnight delivery to the laboratory. You should not collect samples on Friday , Saturday, or Sunday because sampling on these days may not allow samples to be shipped and received at the laboratory at the required temperature, unless you have made special arrangements with your laboratory to receive the samples.
(F) Analytical methods. For each contaminant, you must use the re spective analytical methods for List 1, and, if applicable, for List 2, or List 3 that are specif ied in column 3 of Table 1, in paragraph (a)(3) of this section; report values at or above the minimum report ing levels for List 1, and, if applicable, for List 2 Screening Survey, or List 3 Pre-Screen Testing, that ar e specified in column 4 of Table 1, in paragraph (a)(3) of this section; and conduct the quality control procedures specified in paragraph (a)(5) of this section.
(G) Laboratory errors or sampling deviations. If the laboratory data do not meet the required QC criteria, as specified in paragraph (a)(5) of this section, or you do not follow the required sampling procedures, as specified in paragraphs (a)(4) of this section, yo u must resample within 30 days of being informed or becoming aware of these facts. This resampling is not for the purpose of confirmin g previous results, but to correct the sampling or laboratory error. All systems must report the results obtained from the first sampling for each sampling period, except for cases of sampling or laboratory errors. For the purposes of this rule, no samples are to be recollected for the purposes of confirming the results observed in a previous sampling.
(H) Analysis. For the List 1 contaminants, and, if applicable, List 2 Screening Survey, or List 3 PreScreen Testing contaminants, identified in Table 1, pa ragraph (a)(3) of this section, you must arrange for testing by a laboratory that has been approved by EPA according to requirements in paragraph (a)(5)(ii) of this section.
(I) Review and reporting of results. After you have received the laboratory results, you must review, approve, and submit the system information, and sample collection data and test results. You must report the results as provided in §141.35(c)(6).
(ii) Small systems. If you serve 10,000 or fewer people and are notified that you are part of the State Monitoring Plan for Assessment Monitoring, Screeni ng Survey or Pre-Screen monitoring, you must comply with the requirements specified in paragra phs (a)(4)(i)(A) through (H) of this section. If EPA or the State informs you that they will be collecting your UCMR samples, you must assist them in identifying the appropriate sampling locations and in collecting the samples.

(A) Monitoring period and frequency. You must collect samples at the times specified for you by the State or EPA. Your schedule must follow both the timing of monitoring specified in Table 1, List 1, and, if applicable, List 2, or List 3, and the frequency of monitoring in Table 2 of this section.

(B) Location. You must collect samples at the locations specified for you by the State or EPA.
(C) Sample kits. You must store and maintain the sample collection kits sent to you by the UCMR Sampling Coordinator in accordance with the kit's inst ructions. The sample kit will include all necessary containers, packing materials and cold packs, in structions for collecting the sample and sample treatment (such as dechlor ination or preservation), report forms for each sample, contact name and telephone number for the laboratory, and a prepaid return shipping docket and return address label. If any of the materials listed in the kit's instructions ar e not included in the kit or arrive damaged, you must notify the UCMR Sampling Coordinator wh o sent you the sample collection kits.
(D) Sampling instructions. You must comply with the instructions sent to you by the State or EPA concerning the use of containers, co llection (how to fill the sample bottle), dechlorination and/or preservation, and sealing and prepar ation of sample and shipping containers for shipment. You must not 

## Contaminant type Water source type Time frame Frequency Chemical Surface water or ground water under the direct influence of surface water (GWUDI) (includes all sa mpling locations for which some or all of the water comes from a surface water or GWUDI source at any time during the 12 month monitoring period) 12 months You must monitor for 4 consecutive quarters. Sample events must occur 3 months apart.

Ground water 12 months You must monitor twice in a consecutive 12- month period. Sample events must occur 5–7 months apart. 

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...composite (that is, combine, mix, or blend) the sample s. You also must collect, preserve, and test each sample separately. You must also comply with the instructions sent to you by the UCMR Sampling Coordinator concerning the handling of sample containers for spec ific contaminants.

(E) Sampling deviations. If you do not collect a sample according to the instructions provided to you for a listed contaminant, you must report the deviation within 7 days of the scheduled monitoring on the sample reporting form, as specified in §141.35(d)(2). You must resample following instructions that you will be sent from the UCMR Sampling Coordinator or State. A copy of the form must be sent to the laboratory with the recollected samples, and to the UCMR Sampling Coordinator.

(F) Duplicate samples. EPA will select a subset of systems in the State Monitoring Plan that must collect duplicate samples for quality control. If your system is selected, you will receive two sample kits for an individual sampling location that you must use. You must use the same sampling protocols for both sets of samples, following the instructions in the duplicate sample kit.

(G) Sampling forms. You must completely fill out each of the samp ling forms and bottles sent to you by the UCMR Sampling Coordinator, including data elements listed in §141.35(e) for each sample. If you are conducting Assessment Monitoring, you must in clude elements 1 through 5, and 7; and if you are conducting Screening Su rvey, you must include elements 1 through 7. You must sign and date the sampling forms.
(H) Sample collection and shipping. You must collect the samples early enough in the day to allow adequate time to send the samples for overnight deli very to the laboratory. You should not collect samples on Friday, Saturday, or Sunday because sampling on these days may not allow samples to be shipped and received at the laboratory at the required temperature unless you have made special arrangements with EPA for the laboratory to receive the samples. Once you have collected the samples and completely filled in the sampling forms, you must send the samples and the sampling forms to the laboratory designated on the air bill.
(5) Quality control requirements. If your system serves more than 10,000 people, you must ensure that the quality control requirements listed below are met during your sampling procedures and by the laboratory conducting your analyses. You must al so ensure that all method quality control procedures and all UCMR quality control procedures are followed.

(i) Sample collection/preservation . You must follow the sample collection and preservation requirements for the specified method for each of the contami nants in Table 1, in paragraph (a)(3) of this section. These requirements specify sample containers, co llection, dechlorination, pres ervation, storage, sample holding time, and extract stora ge and/or holding time that you must assure that the laboratory follow.
(ii) Laboratory approval for Lists 1, List 2 and List 3. To be approved to conduct UCMR testing, the laboratory must be certified under §141.28 for one or more compliance analyses; demonstrate for each analytical method it plans to use for UCMR testing that it can meet the Initial Demonstration of Capability (IDC) requirements detailed in the analytical methods specified in column 3 of Table 1, in paragraph (a) (3) of this section; and successfully participate in the UCMR Proficiency Testing (PT) Program administered by EPA for each analytic al method it plans to use for UCMR testing. UCMR laboratory approval decisions will be granted on an individual method basis for t he methods listed in column 3 of Table 1 in paragraph (a)(3) of this section for List 1, List 2, and List 3 conta minants. Laboratory approval is contingent upon the capability of the laboratory to post monitoring data to the EPA electronic data reporting system. To participate in the UCMR Laboratory Approval Program, the laboratory must complete and submit the necessary registration forms by April 4, 2007. Correspondence must be addressed to: UCMR 2 Laboratory Approval Coordinator, USEPA, Technical Support Center, 26 West Martin Luther King Drive (MS 140), Cincinnati, OH 45268; or e-mailed to EPA at UCMR_Sampling_Coordinator@epa.gov

. (iii) Minimum Reporting Level. The MRL is the lowest analyte concentration for which future recovery is predicted to fall, with high confidence (at least 99%), between 50% and 150% recovery.
(A) Validation of laboratory performance. Your laboratory must be capable of quantifying each contaminant listed in Table 1, at or below the MRL specified in column 4 of Table 1, in paragraph (a)(3) of this section. You must ensure that the laboratory co mpletes and has on file and available for your inspection, records of two distinct procedures. First, your laboratory must have conducted an IDC involving replicate analyses at or below the MRL as described in this paragraph. Second, for each day that UCMR analyses are conducted by your laboratory, a validation of its abi lity to quantify each contaminant, at or below the MRL specified in column 4 of Table 1, in paragraph (a)(3) of this section, following the procedure listed in paragraph (a)(5) (iii)(B) of this section, must be performed. The procedure for initial validation of laboratory performance at or below the MRL is as follows:
( 1 ) All laboratories using EPA drinking water methods under UCMR must demonstrate that they are capable of meeting data quality objectives (DQOs) at or below the MRL listed in Table 1, column 4, in paragraph (a)(3) of this section.
( 2 ) The MRL, or any concentration below the MRL, at which performance is being evaluated, must be contained within the range of calibration. The calibration curve regression model and the range of calibration levels that are used in these performance validation steps must be used in all routine sample analyses used to comply with this regulation. Only straight line or quadratic regression models are allowed. The use of either weighted or unweighted models is permitted. The use of cubic regression models is not permitted.
( 3 ) Replicate analyses of at least seven (7) fortified samples in reagent water must be performed at or below the MRL for each analyte, and must be processed through the entire method procedure ( i.e.
, including extraction, where applic able, and with all preservatives).
( 4 ) A prediction interval of results (PIR), which is based on the estimated arithmetic mean of analytical results and the estimated sample standard deviation of measurement results, must be determined by Equation 1:



### Where:

t is the Student's t value with df degrees of freedom and confidence level (1– α ),

s is the sample standard deviation of n replicate samples fortified at the MRL, 

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...

### n is the number of replicates.

( 5 ) The values needed to calculate the PIR usin g Equation 1 are: Number of replicates ( n ); Student's t value with a two-sided 99% confidence level for n number of replicates; the average (mean) of at least seven replicates; and the sample standard deviation. Factor 1 is referred to as the Half Range PIR (HR PIR ).

For a certain number of replicates and for a certain confidence level in Student's t , this factor

is constant, and can be tabulated ac cording to replicate number and confidence level for the Student's t

. Table 3 in this paragraph lis ts the constant factor ( C ) for replicate sample numbers 7 through 10 with a confidence level of 99% for Student's t

. ( 6 ) The HRPIR is calculated by Equation 2:

( 7 ) The PIR is calculated by Equation 3:

Table 3—The Constant Factor (C) to be Multiplied by the Standard Deviation to Determine the Half Range Interval of the PIR (Student's t 99% Confidence Level) a

a The critical t -value for a two-sided 99% confidence in terval is equivalent to the critical t -value for a one-sided 99.5% confidence interval, due to the symmetry of the t -distribution. PIR = Prediction Interval of Results.
( 8 ) The lower and upper result limits of the PIR must be converted to percent recovery of the concentration being tested. To pass criteria at a certain level, the PIR lower recovery limits cannot be lower than the lower recovery limits of the QC interv al (50%), and the PIR upper recovery limits cannot be greater than the upper recovery limits of the QC interval (150%). When either of the PIR recovery limits falls outside of either bound of the QC interv al of recovery (higher than 150% or less than 50%), laboratory performance is not validated at the conc entration evaluated. If the PIR limits are contained within both bounds of the QC interval, laboratory performance is validated for that analyte.
(B) Quality control requirements for validation of laboratory performance at or below the MRL.

( 1 ) You must ensure that the calibration curve regression model and that the range of calibration levels that are used in these performance validation steps are used in future routine sample analysis. Only straight line or quadratic regression models are al lowed. The use of either weighted or unweighted models is permitted. The use of cubic regression models is not permitted.
( 2 ) You must ensure, once your laboratory has performed an IDC as specified in each analytical method (demonstrating that DQOs are met at or below an MRL), that a daily performance check is performed for each analyte and method. A single laboratory blank, fortified at or below the MRL for each analyte, must be processed through the entire method procedure. The measured concentration for each analyte must be converted to a perc ent recovery, and if the recovery is within 50%–150% (inclusive), the daily performance of the laboratory has been validated. The results for any analyte for which 50%–150% recovery cannot be demonstrated during the daily check are not valid. Laboratories may elect to re-run the daily performance check sample if the performanc e for any analyte or analytes cannot be validated. If performance is validated for these analytes, the laboratory performance is considered validated. A lternatively, the laboratory may re-calibrate and repeat the performance validation process for all analytes.
(iv) Laboratory fortified sample matrix and laboratory fortified sample matrix duplicate. You must ensure that your laboratory prepares and analyzes the Laborato ry Fortified Sample Matrix (LFSM) sample for accuracy and Laboratory Fortified Sample Matrix Duplicate (LFSMD) samples for precision to determine method accuracy and precision for all contaminants in Table 1, in paragraph (a)(3) of this section. LFSM/LFSMD samples must be prepared using a sample collected and analyzed in accordance with UCMR 2 requirements and analyzed at a frequency of 5% (or 1 LFSM/LFSMD set per every 20 samples) or with each sample batch, whichever is more frequent. In addition, the LFSM/LFSMD fortification conc entrations must be alternated between a low-leve l fortification and mid-level fortification approximately 50% of the time. (For example: A set of 40 samples will require preparation and analysis of 2 LFSM/LFSMD sets. The fi rst set must be fortified at either the low-level or mid-level, and the second set must be fortified with the other standard, either the low-level or mid-level, whichever was not used for the initial LFSM/LFSMD set.) The low-level LFSM/LF SMD fortification concentration must be within ±50% of the MRL for each contaminant (e.g., for an MRL of 1 μ g/L the acceptable fortification levels must be between 0.5 μ g/L and 1.5 μ g/L). The mid-level LFSM/LFSMD fortification concentration must be within ±20% of the mid-level calibration standard for each contaminant, and should represent, where possible and where the laboratory has data from prev iously analyzed samples, an approximate average concentration observed in previous analyses of that analyte. There are no accepta nce criteria specified for LFSM/LFSMD analyses. All LFSM/LFSMD data are to be reported. 

## Replicates Degrees of freedom Constant factor (C) to be multiplied by the standard deviation 7 6 3.963 8 7 3.711 9 8 3.536 10 9 3.409 

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...(v) Method defined quality control. You must ensure that your laboratory performs Laboratory Fortified Blanks and Laboratory Performance Checks, as appropriate to the method's re quirements, for those methods listed in Table 1, column 3, in paragraph (a)(3) of this section. Each method specifies acceptance criteria for these QC checks.

(vi) Reporting. You must ensure that your laboratory reports the analytical results and other data, with the required data listed in Table 1, in §141.35(e). Y ou must require your laboratory to submit these data electronically to the State and EPA using EPA's electronic data reporting system, accessible at ( http://www.epa.gov/safewater/ucmr/ucmr2/reporting.html ), within 120 days from the sample collection date. You then have 60 days from when the laboratory posts the data to review, approve, and submit the data to the State and EPA, via EPA's electronic data reporting system. If you do not electronically approve and submit the laboratory data to EPA wi thin 60 days of the laboratory's posting to EPA's electronic reporting system, the data will be considered approved and final for State and EPA review.
(6) Violation of this rule —(i) Monitoring violations. Any failure to monitor in accordance with §141.40(a) (3)–(5) is a monitoring violation.

(ii) Reporting violations. Any failure to report in accordanc e with §141.35 is a reporting violation.
(b) Petitions and waivers by States —(1) Governors' petition for additional contaminants. The Safe Drinking Water Act allows Governors of seven (7) or more States to petition the EPA Administrator to add one or more contaminants to the UCMR Contaminant List in paragraph (a)(3) of this section. The petition must clearly identify the reason(s) for addi ng the contaminant(s) to the monitoring list, including the potential risk to public health, particularly any information that might be available regarding disproportional risks to the health and safety of childr en, the expected occurrence documented by any available data, any analytical methods known or pr oposed to be used to test for the contaminant(s), and any other information that could assist the Administrator in determining which contaminants present the greatest public health concern and should, therefore, be included on the UCMR Contaminant List in paragraph (a)(3) of this section.

(2) State-wide waivers. A State can waive monitoring requirements only with EPA approval and under very limited conditions. Conditions and proc edures for obtaining a waiver are as follows:
(i) Application. A State may apply to EPA for a State-wide wa iver from the unregulated contaminant monitoring requirements for PWSs se rving more than 10,000 people. To apply for such a waiver, the State must submit an application to EPA that includes the following information: The list of contaminants on the UCMR Contaminant List for which a waiver is requested, along with documentation for each contaminant in the request demonstrating that the contam inants or their parent compounds do not occur naturally in the State, and certifying that during the past 15 years they have not been used, applied, stored, disposed of, released, or detected in the s ource waters or distribution systems in the State.

(ii) Approval. EPA will review State applications and notify th e State whether it accepts or rejects the request. The State must receive written approval from EPA before issuing a State-wide waiver.

[72 FR 393, Jan. 4, 2007; 72 FR 3916, Jan. 26, 2007]


### § 141.41 Special monitoring for sodium.

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(a) Suppliers of water for community public water systems shall collect and analyze one sample per plant at the entry point of the distribution system for the determination of sodi um concentration levels; samples must be collected and analyzed annually for systems utilizing surface water sources in whole or in part, and at least every three years for systems utilizing solely ground water sources. The minimum number of samples required to be taken by the sys tem shall be based on the number of treatment plants used by the system, except that multiple wells draw ing raw water from a single aquifer may, with the State approval, be considered one treatment plant fo r determining the minimum number of samples. The supplier of water may be required by the State to collect and analyze water samples for sodium more frequently in locations where th e sodium content is variable.
(b) The supplier of water shall report to EPA and/or the State the results of the analyses for sodium within the first 10 days of the month following the month in which the sample results were received or within the first 10 days following the end of the re quired monitoring period as stipulated by the State, whichever of these is first. If more than annual sampli ng is required the supplier shall report the average sodium concentration within 10 days of the month fo llowing the month in which the analytical results of the last sample used for the annual average was received. The supplier of water shall not be required to report the results to EPA where the State has adopted this regulation and results are reported to the State. The supplier shall report the results to EPA where the State has not adopted this regulation.

(c) The supplier of water shall notify appropriate local and State public health officials of the sodium levels by written notice by direct mail within three m onths. A copy of each notice required to be provided by this paragraph shall be sent to EPA and/or the Sta te within 10 days of its issuance. The supplier of water is not required to notify appropriate local and State public health officials of the sodium levels where the State provides such notices in lieu of the supplier.

(d) Analyses for sodium shall be c onducted as directed in §141.23(k)(1).

[45 FR 57345, Aug. 27, 1980, as amended at 59 FR 62470, Dec. 5, 1994]


### § 141.42 Special monitoring for corrosivity characteristics.

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(a)–(c) [Reserved]

(d) Community water supply systems shall identify whether the follo wing construction materials are present in their distribution system and report to the State:


### Lead from piping, solder, caulking, interior lining of distribution mains, alloys and home plumbing.
Copper from piping and alloys, service lines, and home plumbing. 

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...

### Galvanized piping, service lines, and home plumbing.
Ferrous piping materials such as cast iron and steel.

Asbestos cement pipe.

In addition, States may require identi fication and reporting of other mater ials of construction present in distribution systems that may contribute contaminants to the drinking water, such as:


### Vinyl lined asbestos cement pipe.
Coal tar lined pipes and tanks.

[45 FR 57346, Aug. 27, 1980; 47 FR 10999, Mar. 12, 1982, as amended at 59 FR 62470, Dec. 5, 1994]


### § 141.43 Prohibition on use of lead pipes, solder, and flux.

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(a) In general —(1) Prohibition. Any pipe, solder, or flux, which is used after June 19, 1986, in the installation or repair of—
(i) Any public water system, or

(ii) Any plumbing in a residential or nonresidential facility providing water for human consumption which is connected to a public water system shall be lead free as defined by paragraph (d) of this section. This paragraph (a)(1) shall not apply to leaded joints necessary for the repair of cast iron pipes.

(2) [Reserved]
(b) State enforcement— (1) Enforcement of prohibition. The requirements of paragraph (a)(1) of this section shall be enforced in all States effective Ju ne 19, 1988. States shall enforce such requirements through State or local plumbing codes, or such other means of enforcement as the State may determine to be appropriate.
(2) [Reserved]

(c) Penalties. If the Administrator determines that a State is not enforcing the requirements of paragraph (a) of this section, as required pursuant to paragraph (b) of this section, the Administrator may withhold up to 5 percent of Federal funds available to that State for State program grants under section 1443(a) of the Act.

(d) Definition of lead free. For purposes of this section, the term lead free:
(1) When used with respect to solders and flux refe rs to solders and flux containing not more than 0.2 percent lead;
(2) When used with respect to pi pes and pipe fittings refers to pipes and pipe fi ttings containing not more than 8.0 percent lead; and
(3) When used with respect to pl umbing fittings and fixtures intended by the manufacturer to dispense water for human ingestion refers to fittings and fixtures that are in compliance with standards established in accordance with 42 U.S.C. 300g–6(e).

[52 FR 20674, June 2, 1987, as amended at 65 FR 2003, Jan. 12, 2000]


### Subpart F—Maximum Contaminant Level Goals and Maximum Residual Disinfectant Level Goals

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### § 141.50 Maximum contaminant level goals for organic contaminants.

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(a) MCLGs are zero for the following contaminants:
(1) Benzene
(2) Vinyl chloride

(3) Carbon tetrachloride
(4) 1,2-dichloroethane
(5) Trichloroethylene

(6) Acrylamide
(7) Alachlor
(8) Chlordane

(9) Dibromochloropropane 

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...(10) 1,2-Dichloropropane
(11) Epichlorohydrin
(12) Ethylene dibromide
(13) Heptachlor

(14) Heptachlor epoxide
(15) Pentachlorophenol
(16) Polychlorinated biphenyls (PCBs)

(17) Tetrachloroethylene
(18) Toxaphene
(19) Benzo[a]pyrene

(20) Dichloromethane (methylene chloride)
(21) Di(2-ethylhexyl)phthalate
(22) Hexachlorobenzene

(23) 2,3,7,8-TCDD (Dioxin)
(b) MCLGs for the following c ontaminants are as indicated:

[50 FR 46901, Nov. 13, 1985, as amended at 52 FR 20674, June 2, 1987; 52 FR 25716, July 8, 1987; 56 FR 3592, Jan. 30, 1991; 56 FR 30280, July 1, 1991; 57 FR 31846, July 17, 1992]


### § 141.51 Maximum contaminant level goals for inorganic contaminants.

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## Contaminant MCLG in mg/l (1) 1,1-Dichloroethylene 0.007 (2) 1,1,1-Trichloroethane 0.20 (3) para-Dichlorobenzene 0.075 (4) Aldicarb 0.001 (5) Aldicarb sulfoxide 0.001 (6) Aldicarb sulfone 0.001 (7) Atrazine 0.003 (8) Carbofuran 0.04 (9) o-Dichlorobenzene 0.6 (10) cis-1,2-Dichloroethylene 0.07 (11) trans-1,2-Dichloroethylene 0.1 (12) 2,4-D 0.07 (13) Ethylbenzene 0.7 (14) Lindane 0.0002 (15) Methoxychlor 0.04 (16) Monochlorobenzene 0.1 (17) Styrene 0.1 (18) Toluene 1 (19) 2,4,5-TP 0.05 (20) Xylenes (total) 10 (21) Dalapon 0.2 (22) Di(2-ethylhexyl)adipate .4 (23) Dinoseb .007 (24) Diquat .02 (25) Endothall .1 (26) Endrin .002 (27) Glyphosate .7 (28) Hexachlorocyclopentadiene .05 (29) Oxamyl (Vydate) .2 (30) Picloram .5 (31) Simazine .004 (32) 1,2,4-Trichlorobenzene .07 (33) 1,1,2-Trichloroethane .003 

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...(a) [Reserved]
(b) MCLGs for the following c ontaminants are as indicated:

1 This value for arsenic is effective January23, 2006. Until then, there is no MCLG.

[50 FR 47155, Nov. 14, 1985, as amended at 52 FR 20674, June 2, 1987; 56 FR 3593, Jan. 30, 1991; 56 FR 26548, June 7, 1991; 56 FR 30280, July 1, 1991; 57 FR 31846, July 17, 1992; 60 FR 33932, June 29, 1995; 66 FR 7063, Jan. 22, 2001]


### § 141.52 Maximum contaminant level goals for microbiological contaminants.

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MCLGs for the following conta minants are as indicated:

[54 FR 27527, 27566, June 29, 1989; 55 FR 25064, June 19, 1990; 63 FR 69515, Dec. 16, 1998]


### § 141.53 Maximum contaminant level goals for disinfection byproducts.

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MCLGs for the following disinfecti on byproducts ar e as indicated:

[63 FR 69465, Dec. 16, 1998, as amended at 65 FR 34405, May 30, 2000; 71 FR 478, Jan. 4, 2006]


### § 141.54 Maximum residual disinfectant level goals for disinfectants.

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MRDLGs for disinfectants are as follows: 

## Contaminant MCLG (mg/l) Antimony 0.006 Arsenic zero 1 

## Asbestos 7 Million fibers/liter (longer than 10 μm). Barium 2 Beryllium .004 Cadmium 0.005 Chromium 0.1 Copper 1.3 Cyanide (as free Cyanide) .2 Fluoride 4.0 Lead zero Mercury 0.002 Nitrate 10 (as Nitrogen). Nitrite 1 (as Nitrogen). Total Nitrate+Nitrite 10 (as Nitrogen). Selenium 0.05 Thallium .0005

Contaminant MCLG (1) Giardia lamblia zero (2) Viruses zero (3) Legionella zero (4) Total coliforms (including fecal coliforms and Escherichia coli ) zero. (5) Cryptosporidiumzero.

Disinfection byproduct MCLG (mg/L) Bromodichloromethane zero Bromoform zero Bromate zero Chlorite 0.8 Chloroform 0.07 Dibromochloromethane 0.06 Dichloroacetic acid zero Monochloroacetic acid 0.07 Trichloroacetic acid 0.02 

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...[63 FR 69465, Dec. 16, 1998]


### § 141.55 Maximum contaminant level goals for radionuclides.

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MCLGs for radionuclides are as indicated in the following table:

[65 FR 76748, Dec. 7, 2000]


### Subpart G—National Primary Drinking Water Regulations: Maximum Contaminant Levels and Maximum Residual Disinfectant Levels

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### § 141.60 Effective dates.

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(a) The effective dates for §141.61 are as follows:

(1) The effective date for paragraphs (a)(1) through (a)(8) of §141.61 is January 9, 1989.
(2) The effective date for paragraphs (a)(9) through (a )(18) and (c)(1) through (c)(18) of §141.61 is July 30, 1992.
(3) The effective date for paragraphs (a)(19) through (a)(21), (c)(19) through (c)(25), and (c)(27) through (c)(33) of §141.61 is January 17, 1994. The effective date of §141.61(c)(26) is August 17, 1992.
(b) The effective dates for §141.62 are as follows:
(1) The effective date of paragraph (b)(1) of §141.62 is October 2, 1987.
(2) The effective date for paragraphs (b)(2) and (b)(4) through (b)(10) of §141.62 is July 30, 1992.
(3) The effective date for paragraphs (b)(11) through (b)(15) of §141.62 is January 17, 1994.

(4) The effective date for §141.62(b)(16) is January 23, 2006.

[56 FR 3593, Jan. 30, 1991, as amended at 57 FR 31846, July 17, 1992; 59 FR 34324, July 1, 1994; 66FR 7063, Jan. 22, 2001]


### § 141.61 Maximum contaminant levels for organic contaminants.

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(a) The following maximum contaminant levels for organic contaminants apply to community and nontransient, non-community water systems. 

## Disinfectant residual MRDLG(mg/L) Chlorine 4 (as Cl 2 

## ). Chloramines 4 (as Cl 2 

## ). Chlorine dioxide 0.8 (as ClO 2 

## )

Contaminant MCLG 1. Combined radium-226 and radium-228 Zero. 2. Gross alpha particle activity (excluding radon and uranium) Zero. 3. Beta particle and photon radioactivity Zero. 4. Uranium Zero.

CAS No. Contaminant MCL (mg/l) (1) 75–01–4 Vinyl chloride 0.002 (2) 71–43–2 Benzene 0.005 (3) 56–23–5 Carbon tetrachloride 0.005 (4) 107–06–2 1,2-Dichloroethane 0.005 (5) 79–01–6 Trichloroethylene 0.005 (6) 106–46–7 para-Dichlorobenzene 0.075 (7) 75–35–4 1,1-Dichloroethylene 0.007 (8) 71–55–6 1,1,1-Trichloroethane 0.2 (9) 156–59–2 cis-1,2-Dichloroethylene 0.07 (10) 78–87–5 1,2-Dichloropropane 0.005 (11) 100–41–4 Ethylbenzene 0.7 (12) 108–90–7 Monochlorobenzene 0.1 

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...(b) The Administrator, pursuant to section 1412 of the Act, hereby identifies as indicated in the Table below granular activated carbon (GAC), packed tower aeration (PTA), or oxidation (OX) as the best technology treatment technique, or other means ava ilable for achieving comp liance with the maximum contaminant level for organic contaminants identif ied in paragraphs (a) and (c) of this section:
BAT for Organic Contaminants Listed in §141.61 (a) and (c) 

## (13) 95–50–1 o-Dichlorobenzene 0.6 (14) 100–42–5 Styrene 0.1 (15) 127–18–4 Tetrachloroethylene 0.005 (16) 108–88–3 Toluene 1 (17) 156–60–5 trans-1,2-Dichloroethylene 0.1 (18) 1330–20–7 Xylenes (total) 10 (19) 75–09–2 Dichloromethane 0.005 (20) 120–82–1 1,2,4-Trichloro- benzene .07 (21) 79–00–5 1,1,2-Trichloro- ethane .005

CAS No. Contaminant GAC PTA OX 15972–60–8 Alachlor X 116–06–3 Aldicarb X 1646–88–4 Aldicarb sulfone X 1646–87–3 Aldicarb sulfoxide X 1912–24–9 Atrazine X 71–43–2 Benzene X X 50–32–8 Benzo[a]pyrene X 1563–66–2 Carbofuran X 56–23–5 Carbon tetrachloride X X 57–74–9 Chlordane X 75–99–0 Dalapon X 94–75–7 2,4-D X 103–23–1 Di (2-ethylhexyl) adipate X X 117–81–7 Di (2-ethylhexyl) phthalate X 96–12–8 Dibromochloropropane (DBCP) X X 95–50–1 o-Dichlorobenzene X X 106–46–7 para-Dichlorobenzene X X 107–06–2 1,2-Dichloroethane X X 75–35–4 1,1-Dichloroethylene X X 156–59–2 cis-1,2-Dichloroethylene X X 156–60–5 trans-1,2-Dichloroethylene X X 75–09–2 Dichloromethane X 78–87–5 1,2-Dichloropropane X X 88–85–7 Dinoseb X 85–00–7 Diquat X 145–73–3 Endothall X 72–20–8 Endrin X 100–41–4 Ethylbenzene X X 106–93–4 Ethylene Dibromide (EDB) X X 1071–83–6 Gylphosate X 76–44–8 Heptachlor X 1024–57–3 Heptachlor epoxide X 118–74–1 Hexachlorobenzene X 77–47–3 Hexachlorocyclopentadiene X X 58–89–9 Lindane X 72–43–5 Methoxychlor X 108–90–7 Monochlorobenzene X X 23135–22–0 Oxamyl (Vydate) X 87–86–5 Pentachlorophenol X 1918–02–1 Picloram X 1336–36–3 Polychlorinated biphenyls (PCB) X 122–34–9 Simazine X 100–42–5 Styrene X X 1746–01–6 2,3,7,8-TCDD (Dioxin) X 127–18–4 Tetrachloroethylene X X 108–88–3 Toluene X X 8001–35–2 Toxaphene X 

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...(c) The following maximum contaminant levels forsynthetic organic contaminants apply to community water systems and non-transient, non-community water systems:

[56 FR 3593, Jan. 30, 1991, as amended at 56 FR 30280, July 1, 1991; 57 FR 31846, July 17, 1992; 59 FR 34324, July 1, 1994]


### § 141.62 Maximum contaminant levels for inorganic contaminants.

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(a) [Reserved]

(b) The maximum contaminant levels for inorganic co ntaminants specified in paragraphs (b) (2)–(6), (b) (10), and (b) (11)–(16 ) of this section apply to community w ater systems and non-transient, noncommunity water systems. The maximum contaminant leve l specified in paragraph (b)(1) of this section only applies to community water systems. The maximu m contaminant levels specified in (b)(7), (b)(8), and (b)(9) of this section apply to community water systems; non-transient, non-community water systems; and transient non-community water systems. 

## 93–72–1 2,4,5-TP (Silvex) X 120–82–1 1,2,4-Trichlorobenzene X X 71–55–6 1,1,1-Trichloroethane X X 79–00–5 1,1,2-Trichloroethane X X 79–01–6 Trichloroethylene X X 75–01–4 Vinyl chloride X 1330–20–7 Xylene X X

CAS No. Contaminant MCL (mg/l) (1) 15972–60–8 Alachlor 0.002 (2) 116–06–3 Aldicarb 0.003 (3) 1646–87–3 Aldicarb sulfoxide 0.004 (4) 1646–87–4 Aldicarb sulfone 0.002 (5) 1912–24–9 Atrazine 0.003 (6) 1563–66–2 Carbofuran 0.04 (7) 57–74–9 Chlordane 0.002 (8) 96–12–8 Dibromochloropropane 0.0002 (9) 94–75–7 2,4-D 0.07 (10) 106–93–4 Ethylene dibromide 0.00005 (11) 76–44–8 Heptachlor 0.0004 (12) 1024–57–3 Heptachlor epoxide 0.0002 (13) 58–89–9 Lindane 0.0002 (14) 72–43–5 Methoxychlor 0.04 (15) 1336–36–3 Polychlorinated biphenyls 0.0005 (16) 87–86–5 Pentachlorophenol 0.001 (17) 8001–35–2 Toxaphene 0.003 (18) 93–72–1 2,4,5-TP 0.05 (19) 50–32–8 Benzo[a]pyrene 0.0002 (20) 75–99–0 Dalapon 0.2 (21) 103–23–1 Di(2-ethylhexyl) adipate 0.4 (22) 117–81–7 Di(2-ethylhexyl) phthalate 0.006 (23) 88–85–7 Dinoseb 0.007 (24) 85–00–7 Diquat 0.02 (25) 145–73–3 Endothall 0.1 (26) 72–20–8 Endrin 0.002 (27) 1071–53–6 Glyphosate 0.7 (28) 118–74–1 Hexacholorbenzene 0.001 (29) 77–47–4 Hexachlorocyclopentadiene 0.05 (30) 23135–22–0 Oxamyl (Vydate) 0.2 (31) 1918–02–1 Picloram 0.5 (32) 122–34–9 Simazine 0.004 (33) 1746–01–6 2,3,7,8-TCDD (Dioxin) 3×10 − 8



## Contaminant MCL (mg/l) (1) Fluoride 4.0 (2) Asbestos 7 Million Fibers/ liter (longer than 10 μm). (3) Barium 2 (4) Cadmium 0.005 (5) Chromium 0.1 

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...(c) The Administrator, pursuant to section 1412 of th e Act, hereby identifies the following as the best technology, treatment technique, or othe r means available forachieving compliance with the maximum contaminant levels for inorganic contam inants identified in paragraph (b) of this section, except fluoride:

BAT for Inorganic Compounds Listed in Section 141.62(b)

1 BAT only if influent Hg concentrations ≤ 10μg/1.

2 BAT for Chromium III only.

3 BAT for Selenium IV only.

4 BATs for Arsenic V. Pre-oxidation may be required to convert Ars enic III to Arsenic V.

5 To obtain high removals, iron to arsenic ratio must be at least 20:1.
Key to BATS in Table



### 1 = Activated Alumina
2 = Coagulation/Filtration (not BAT for systems < 500 service connections)

3 = Direct and Diatomite Filtration

4 = Granular Activated Carbon
5 = Ion Exchange
6 = Lime Softening (not BAT for systems <500 service connections)

7 = Reverse Osmosis

8 = Corrosion Control
9 = Electrodialysis

10 = Chlorine

11 = Ultraviolet

12 = Oxidation/Filtration
13 = Alkaline Chlorination (pH ≥ 8.5) 

## (6) Mercury 0.002 (7) Nitrate 10 (as Nitrogen) (8) Nitrite 1 (as Nitrogen) (9) Total Nitrate and Nitrite 10 (as Nitrogen) (10) Selenium 0.05 (11) Antimony 0.006 (12) Beryllium 0.004 (13) Cyanide (as free Cyanide) 0.2 (14) [Reserved] (15) Thallium 0.002 (16) Arsenic 0.010

Chemical Name BAT(s) Antimony 2,7 Arsenic4 

## 1, 2, 5, 6, 7, 9, 12 5 

## Asbestos 2,3,8 Barium 5,6,7,9 Beryllium 1,2,5,6,7 Cadmium 2,5,6,7 Chromium 2,5,6 2 

## ,7 Cyanide 5,7,13 Mercury 2 1 

## ,4,6 1 

## ,7 1 

## Nickel 5,6,7 Nitrate 5,7,9 Nitrite 5,7 Selenium 1,2 3 

## ,6,7,9 Thallium 1,5 

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...(d) The Administrator, pursuant to section 1412 of the Act, hereby identifies in the following table the affordable technology, treatment technique, or other me ans available to systems serving 10,000 persons or fewer for achieving compliance with t he maximum contaminant level for arsenic:

Small System Compliance Technologies (SSCTs) 1 for Arsenic 2

1 Section 1412(b)(4)(E)(ii) of SDWA specifies that SS CTs must be affordable and technically feasible for small systems.

2 SSCTs for Arsenic V. Pre-oxidation may be required to convert Arsenic III to Arsenic V.

3 The Act (ibid.) specifies three categories of small systems: (i) those serving 25 or more, but fewer than 501, (ii) those serving more than 500, but fewer than 3,301, and (iii) those serving more than 3,300, but fewer than 10,001.

4 When POU or POE devices are used for compliance, programs to ensure proper long-term operation, maintenance, and monitoring must be provided by the water system to ensure adequate performance.

5 Unlikely to be installed solely for arsenic removal. May require pH adjustment to optimal range if high removals are needed.

6 Technologies reject a large volume of water—maynot be appropriate for areas where water quantity may be an issue.

7 To obtain high removals, iron to arsenic ratio must be at least 20:1.

[56 FR 3594, Jan. 30, 1991, as amended at 56 FR 30280, July 1, 1991; 57 FR 31847, July 17, 1992; 59 FR 34325, July 1, 1994; 60 FR 33932, June 29, 1995; 66 FR 7063, Jan. 22, 2001; 68 FR 14506, Mar. 25, 2003; 69 FR 38855, June 29, 2004]


### § 141.63 Maximum contaminant levels (MCLs) for microbiological contaminants.

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(a) The MCL is based on the presence or absence of to tal coliforms in a sample, rather than coliform density.
(1) For a system which collects at least 40 samp les per month, if no more than 5.0 percent of the samples collected during a month are total coliform-positive, the system is in compliance with the MCL for total coliforms.

(2) For a system which collects fewer than 40 samples/month, if no more than one sample collected during a month is total coliform-positive, the system is in compliance with the MCL for total coliforms.

(b) Any fecal coliform-positive repeat sample or E. coli -positive repeat sample, or any total coliformpositive repeat sample following a fecal coliform-positive or E. coli -positive routine sample constitutes a violation of the MCL for total colifor ms. For purposes of the public noti fication requirements in subpart Q, this is a violation that may pose an acute risk to health.
(c) A public water system must determine compliance with the MCL for total coliforms in paragraphs (a) and (b) of this section for each month in which it is required to monitor for total coliforms.
(d) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or othe r means available for achieving compliance with the maximum contaminant level for total coliforms in paragraphs (a) and (b) of this section:
(1) Protection of wells from contamination by co liforms by appropriate pl acement and construction;
(2) Maintenance of a disinfectant residual throughout the distribution system;
(3) Proper maintenance of the distribution system incl uding appropriate pipe replacement and repair procedures, main flushing programs, proper operation and maintenance of storage tanks and reservoirs, and continual maintenance of positive water pressure in all parts of the distribution system;
(4) Filtration and/or disinfection of surface water, as described in subpart H, or disinfection of ground 

## Small system compliance technology Affordable for listed small system categories 3 

## Activated Alumina (centralized) All size categories. Activated Alumina (Point-of-Use) 4 

## All size categories. Coagulation/Filtration 5 

## 501–3,300, 3,301–10,000. Coagulation-assisted Microfiltration 501–3,300, 3,301–10,000. Electrodialysis reversal 6 

## 501–3,300, 3,301–10,000. Enhanced coagulation/filtration All size categories Enhanced lime softening (pH> 10.5) All size categories. Ion Exchange All size categories. Lime Softening 5 

## 501–3,300, 3,301–10,000.
Oxidation/Filtration 7 

## All size categories. Reverse Osmosis (centralized) 6 

## 501–3,300, 3,301–10,000. Reverse Osmosis (Point-of-Use) 4 

## All size categories. 

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...water using strong oxidants such as ch lorine, chlorine dioxide, or ozone; and
(5) For systems using ground water, compliance with the requirements of an EPA-approved State Wellhead Protection Program developed and implemented under section 1428 of the SDWA.

[54 FR 27566, June 29, 1989; 55 FR 25064, June 19, 1990, as amended at 65 FR 26022, May 4, 2000]


### § 141.64 Maximum contaminant levels for disinfection byproducts.

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(a) Bromate and chlorite. The maximum contaminant levels (MCLs) for bromate and chlorite are as follows:

(1) Compliance dates for CWSs and NTNCWSs. Subpart H systems serving 10,000 or more persons must comply with this paragraph (a) beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not under the direct influence of surface water must comply with this paragraph (a) beginning January 1, 2004.
(2) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or othe r means available for achieving compliance with the maximum contaminant levels for bromate and chlorite identified in this paragraph (a):

(b) TTHM and HAA5. (1) Subpart L—RAA compliance. (i) Compliance dates. Subpart H systems serving 10,000 or more persons must comply with this para graph (b)(1) beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and sy stems using only ground water not under the direct influence of surface water must comply with th is paragraph (b)(1) beginning January 1, 2004. All systems must comply with these MCLs until the date specified for subpart V compliance in §141.620(c).

(ii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or othe r means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph (b)(1):

(2) Subpart V—LRAA compliance. (i) Compliance dates . The subpart V MCLs for TTHM and HAA5 must be complied with as a locational running annual averag e at each monitoring location beginning the date specified for subpart V compliance in §141.620(c).

(ii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or othe r means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph (b)(2) for all systems that disinfect their source water:

(iii) The Administrator, pursuant to section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or othe r means available for achieving compliance with the maximum contaminant levels for TTHM and HAA5 identified in this paragraph (b)(2) for consecutive systems and applies only to the disinfected w ater that consecutive systems buy or otherwise receive: 

## Disinfection byproduct MCL (mg/L) Bromate 0.010 Chlorite 1.0

Disinfection byproduct Best available technology Bromate Control of ozone treatment process to reduce production of bromate Chlorite Control of treatment processes to reduce disinfectant demand and control of disinfection treatment processes to reduce disinfectant levels

Disinfection byproduct MCL (mg/L) Total trihalomethanes (TTHM) 0.080 Haloacetic acids (five) (HAA5) 0.060

Disinfection byproduct Best available technology Total trihalomethanes (TTHM) and Haloacetic acids (five) (HAA5) Enhanced coagulation or enhanced softening or GAC10, with chlorine as the primary and residual disinfectant

Disinfection byproduct MCL (mg/L) Total trihalomethanes (TTHM) 0.080 Haloacetic acids (five) (HAA5) 0.060

Disinfection byproduct Best available technology Total trihalomethanes (TTHM) and Haloacetic acids (five) (HAA5) Enhanced coagulation or enhanced softening, plus GAC10; or nanofiltration with a molecular weight cutoff ≤ 1000 Daltons; or GAC20

Disinfection byproduct Best available technology 

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...[71 FR 478, Jan. 4, 2006]


### § 141.65 Maximum residual disinfectant levels.

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(a) Maximum residual disinfectant levels (MRDLs) are as follows:

(b) Compliance dates —(1) CWSs and NTNCWSs. Subpart H systems serving 10,000 or more persons must comply with this section beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not und er the direct influence of surface water must comply with this subpart beginning January 1, 2004.
(2) Transient NCWSs. Subpart H systems serving 10,0 00 or more persons and us ing chlorine dioxide as a disinfectant or oxidant must comply with the ch lorine dioxide MRDL beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and using chlorine diox ide as a disinfectant or oxidant and systems using only ground water not underthe direct influence of surface water and using chlorine dioxide as a disinfectant or oxidant must comply with the chlorine dioxide MRDL beginning January 1, 2004.
(c) The Administrator, pursuant to Section 1412 of the Act, hereby identifies the following as the best technology, treatment techniques, or othe r means available for achieving compliance with the maximum residual disinfectant levels identified in paragraph (a) of this section: control of treatment processes to reduce disinfectant demand and control of disinfecti on treatment processes to reduce disinfectant levels.

[63 FR 69465, Dec. 16, 1998, as amended at 66 FR 3776, Jan. 16, 2001]


### § 141.66 Maximum contaminant levels for radionuclides.

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(a) [Reserved]
(b) MCL for combined radium-226 and -228. The maximum contaminant level for combined radium-226 and radium-228 is 5 pCi/L. The combined radi um-226 and radium-228 value is determined by the addition of the results of the analysis for radium-226 and the analysis for radium-228.

(c) MCL for gross alpha particle activity (excluding radon and uranium). The maximum contaminant level for gross alpha particle activity (i ncluding radium-226 but excluding radon and uranium) is 15 pCi/L.
(d) MCL for beta particle and photon radioactivity. (1) The average annual concen tration of beta particle and photon radioactivity from man-made radionuclides in drinking water must not produce an annual dose equivalent to the total body or any internal organ greater than 4 millirem/year (mrem/year).
(2) Except for the radionuclides listed in table A, the concentration of man-made radionuclides causing 4 mrem total body or organ dose equivalents must be calculated on the basis of 2 liter per day drinking water intake using the 168 hour data list in “M aximum Permissible Body Burdens and Maximum Permissible Concentrations of Ra dionuclides in Air and in Water for Occupational Exposure,” NBS (National Bureau of Standards) Handbook 69 as amended August 1963, U.S. Department of Commerce. This incorporation by reference was approved by the Director of the Feder al Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of this document are available from the National Technical Information Service, NTIS ADA 280 282, U.S. Department of Commerce, 5285 Port Royal Road, Springfield, Virginia 22161. The toll-free number is 800–553–6847. Copies may be inspected at EPA's Drinking Water Docket, 401 M Street, SW., Washington, DC 20460; or at the National Archives and Records Administration (NARA). For information on the av ailability of this material at NARA, call 202– 741–6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. If two or more radionuclides are present, the sum of their annual dose equivalent to the total body or to any organ shall not exceed 4 mrem/year.
Table A—Average Annual Concentrations Assumed To Produce: a Total Body or Organ Dose of 4 mrem/yr

(e) MCL for uranium. The maximum contaminant level for uranium is 30 μg/L.
(f) Compliance dates. (1) Compliance dates for combined radium-226 and -228, gross alpha particle 

## Total trihalomethanes (TTHM) and Haloacetic acids (five) (HAA5) Systems serving ≥ 10,000: Improved distribution system and storage tank management to reduce residence time, plus the use of chloramines for disinfectant residual maintenance Systems serving <10,000: Improved distribution system and storage tank management to reduce residence time

Disinfectant residual MRDL (mg/L) Chlorine 4.0 (as Cl 2 

## ). Chloramines 4.0 (as Cl 2 

## ). Chlorine dioxide 0.8 (as ClO 2 

## ).

1. Radionuclide Critical organ pCi per liter 2. Tritium Total body 20,000 3. Strontium-90 Bone Marrow 8 

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...activity, gross beta particle and photon radioactivi ty, and uranium: Community water systems must comply with the MCLs listed in paragraphs (b), (c), (d), and (e) of this section beginning December 8, 2003 and compliance shall be determined in accordance with the requirements of §§141.25 and 141.26. Compliance with reporting requirements for the r adionuclides under appendix A to subpart O and appendices A and B to subpart Q is required on December 8, 2003.

(2) [Reserved]
(g) Best available technologies (BATs) for radionuclides. The Administrator, pursuant to section 1412 of the Act, hereby identifies as indi cated in the following table the best technology available for achieving compliance with the maximum contaminant levels for combined radium-226 and -228, uranium, gross alpha particle activity, and beta particle and photon radioactivity.

Table B—BAT for Combined Radium-226 and Radium-228, Uranium, Gross Alpha Particle Activity, and Beta Particle and Photon Radioactivity

(h) Small systems compliance technologies list for radionuclides.
Table C—List of Small Systems Compliance Technologies for Radionuclides and Limitations to Use

1 National Research Council (NRC). Safe Water from Every Tap: Improving Water Service to Small Communities. National Academy Press. Washington, D.C. 1997.

2 A POU, or “point-of-use” technology is a treatmen t device installed at a singl e tap used for the purpose of reducing contaminants in drinking water at that one tap. POU devices are typically installed at the kitchen tap. See the April 21, 2000 NODA for more details.

Limitations Footnotes: Tech nologies for Radionuclides:

a The regeneration solution contains high concentr ations of the contaminant ions. Disposal options should be carefully considered before choosing this technology.

b When POU devices are used for compliance, programs for long-term operation, maintenance, and monitoring must be provided by water utility to ensure proper performance. 

## Contaminant BAT 1. Combined radium-226 and radium-228 Ion exchange, reverse osmosis, lime softening. 2. Uranium Ion exchange, reverse osmosis, lime softening, coagulation/filtration. 3. Gross alpha particle activity (excluding Radon and Uranium) Reverse osmosis.
4. Beta particle and photon radioactivity Ion exchange, reverse osmosis.

Unit technologies Limitations (see footnotes) Operator skill level required 1 

## Raw water quality range and considerations. 1 

## 1. Ion exchange (IE) ( a 

## ) Intermediate All ground waters. 2. Point of use (POU 2 

## ) IE ( b 

## ) Basic All ground waters. 3. Reverse osmosis (RO) ( c 

## ) Advanced Surface watersusually require prefiltration. 4. POU 2 

## RO ( b 

## ) Basic Surface watersusually require prefiltration. 5. Lime softening ( d 

## ) Advanced All waters. 6. Green sand filtration ( e 

## ) Basic. 7. Co-precipitation with Barium sulfate ( f

## ) Intermediate to Advanced Ground waters with suitable water quality. 8. Electrodialysis/electrodialysis reversal Basic to Intermediate All ground waters.

9. Pre-formed hydrous Manganese oxide filtration ( g 

## ) Intermediate All ground waters.

10. Activated alumina ( a 

## ), ( h 

## ) Advanced All ground waters; competing anion concentrations may affect regeneration frequency. 11. Enhanced coagulation/filtration ( i 

## ) Advanced Can treat a wide range of water qualities. 

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...c Reject water disposal options should be carefull y considered before choosing this technology. See other RO limitations described in the SWTR Compliance Technologies Table.

d The combination of variable source water quality and the complexity of the water chemistry involved may make this technology too complex for small surface water systems.

e Removal efficiencies can vary depending on water quality.

f This technology may be very limited in application to small systems. Since th e process requires static mixing, detention basins, and filtration, it is mo st applicable to systems with sufficiently high sulfate levels that already have a suitable filtration treatment train in place.

g This technology is most applicable to small s ystems that already have filtration in place.

h Handling of chemicals required during regeneratio n and pH adjustment may be too difficult for small systems without an adequately trained operator.

i Assumes modification to a coagulation/f iltration process already in place.
Table D—Compliance Technologies by System Size Category for Radionuclide NPDWR's

Note: 1 Numbers correspond to those technologie s found listed in the table C of 141.66(h).

[65 FR 76748, Dec. 7, 2000]


### Subpart H—Filtration and Disinfection

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### Source: 54 FR 27527, June 29, 1989, unless otherwise noted.
§ 141.70 General requirements.

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(a) The requirements of this subpart H constitute national primary dr inking water regulations. These regulations establish criteria under which filtration is required as a treatment technique for public water systems supplied by a surface water source and public water systems supplied by a ground water source under the direct influence of surface water. In addition, these regulati ons establish treatment technique requirements in lieu of maximum contaminant levels for the following contaminants: Giardia lamblia, viruses, heterotrophic plate count bacteria, Legionella, and turbidity. Each public water system with a surface water source or a ground water source under the direct influence of surface water must provide treatment of that source water that compli es with these treatment technique requirements. The treatment technique requirements consist of installi ng and properly operating water treatment processes which reliably achieve:
(1) At least 99.9 percent (3-log) removal and/or inactivation of Giardia lamblia cysts between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer; and

(2) At least 99.99 percent (4-log) removal and/or inactivation of viruses between a point where the raw water is not subject to recontaminati on by surface water runoff and a point downstream before or at the first customer.
(b) A public water system using a surface water s ource or a ground water source under the direct influence of surface water is considered to be in compliance with the requirements of paragraph (a) of this section if:
(1) It meets the requirements for avoiding filtration in §141.71 and the disinfection requirements in §141.72(a); or
(2) It meets the filtration requirements in §141.73 and the disinfection requirements in §141.72(b).

(c) Each public water system using a surface water source or a ground water source under the direct influence of surface water must be operated by qualif ied personnel who meet the requirements specified by the State.

(d) Additional requirements for system s serving at least 10,000 people. In addition to complying with requirements in this subpart, systems serving at least 10,000 people mustalso comply with the requirements in subpart P of this part. 

## Contaminant Compliance technologies 1 

## for system size categories (population served) 3,300– 10,000 25–500 501–3,3001. Combined radium226 and radium-228 1, 2, 3, 4, 5, 6, 7, 8, 9 1, 2, 3, 4, 5, 6, 7, 8, 9 1, 2, 3, 4, 5, 6, 7. 8, 9. 2. Gross alpha particle activity 3, 4 3, 4 3, 4.
3. Beta particle activity and photon activity 1, 2, 3, 4 1, 2, 3, 4 1, 2, 3, 4.
4. Uranium 1, 2, 4, 10, 11 1, 2, 3, 4, 5, 10, 11 1, 2, 3, 4, 5, 10, 11. 

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...(e) Additional requirements for system s serving fewer than 10,000 people. In addition to complying with requirements in this subpart, systems serving fewer than 10,000 people must also comply with the requirements in subpart T of this part.

[54 FR 27527, June 29, 1989, as amended at 63 FR 69516, Dec. 16, 1998; 67 FR 1836, Jan. 14, 2002]


### § 141.71 Criteria for avoiding filtration.

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Apublic water system that uses a surface water source must meet all of the conditions of paragraphs (a) and (b) of this section, and is subject to paragraph (c) of this section, beginning December 30, 1991, unless the State has determined, in writing pursuant to §1412(b)(7)(C)(iii), that filtration is required. A public water system that uses a ground water source under the direct influence of surface water must meet all of the conditions of paragraphs (a) and (b) of this section and is subject to paragraph (c) of this section, beginning 18 months after the State determines that it is under the direct influence of surface water, or December 30, 1991, whichever is later, unless the State has determined, in writing pursuant to §1412(b)(7)(C)(iii), that filtration is required. If the State determines in writing pursuant to §1412(b)(7)(C) (iii) before December 30, 1991, that filtration is required, the system must have installed filtration and meet the criteria for filtered systems specified in §§141.72(b) and 141.73 by June 29, 1993. Within 18 months of the failure of a system using surface water or a ground water source under the direct influence of surface water to meet any one of the requi rements of paragraphs (a) and (b) of this section or after June 29, 1993, whichever is later, the system must have installed filtration and meet the criteria for filtered systems specified in §§141.72(b) and 141.73.
(a) Source water quality conditions. (1) The fecal coliform concentration must be equal to or less than 20/100 ml, or the total coliform concentration mustbe equal to or less than 100/100 ml (measured as specified in §141.74 (a) (1) and (2) and (b)(1)), in representative samples of the source water immediately prior to the first or only point of disinfectant applic ation in at least 90 percent of the measurements made for the 6 previous months that the system served water to the public on an ongoing basis. If a system measures both fecal and total coliforms, the fecal coliform criterion, but not the total coliform criterion, in this paragraph must be met.
(2) The turbidity level cannot exceed 5 NTU (measured as specified in §141.74 (a)(1) and (b)(2)) in representative samples of the source water immediate ly prior to the first or only point of disinfectant application unless: (i) the State dete rmines that any such event was caus ed by circumstances that were unusual and unpredictable; and (ii) as a result of any such event, there have not been more than two events in the past 12 months the system served water to the public, or more than five events in the past 120 months the system served water to the public, in which the turbidity level exceeded 5 NTU. An “event” is a series of consecutive days during wh ich at least one turbidity measurement each day exceeds 5 NTU.
(b) Site-specific conditions. (1)(i) The public water system must meet the requirements of §141.72(a)(1) at least 11 of the 12 previous month s that the system served water to the public, on an ongoing basis, unless the system fails to meet the requirements during 2 of the 12 previous months that the system served water to the public, and the State determines that at least one of these failures was caused by circumstances that were unusual and unpredictable.
(ii) The public water system must meet the requireme nts of §141.72(a)(2) at all times the system serves water to the public.
(iii) The public water system must meet the requirem ents of §141.72(a)(3) at all times the system serves water to the public unless the State determines that an y such failure was caused by circumstances that were unusual and unpredictable.
(iv) The public water system must meet the requirements of §141.72(a)(4) on an ongoing basis unless the State determines that failure to meet these r equirements was not caused by a deficiency in treatment of the source water.

(2) The public water system must maintain a watershed control program which minimizes the potential for contamination by Giardia lamblia cysts and viruses in the source water. The State must determine whether the watershed control program is adequate to meet this goal. The adequacy of a program to limit potential contamination by Giardia lamblia cysts and viruses must be based on: the comprehensiveness of the watershed review; the effectiveness of the system's program to monitor and control detrimental activities occurring in the w atershed; and the extent to which the water system has maximized land ownership and/or controlled land use within the watershed. At a minimum, the watershed control program must:
(i) Characterize the watershed hydrology and land ownership;
(ii) Identify watershed characteristics and activities which may have an adverse effect on source water quality; and
(iii) Monitor the occurrence of ac tivities which may have an adverse effect on source water quality.
The public water system must demonstrate through ownership and/or written agreements with landowners within the watershed that it can control all human activities which may have an adverse impact on the microbiological quality of the source water. The public water system must submit an annual report to the State that identifies any spec ial concerns about the watershed and how they are being handled; describes activities in the watershe d that affect water quality; and projects what adverse activities are expected to occur in the future an d describes how the public water system expects to address them. For systems using a ground water source under the direct influence of surface water, an approved wellhead protection program developed under section 1428 of the Safe Drinking Water Act may be used, if the State deems it appropriate, to meet these requirements.
(3) The public water system must be subject to an annual on-site inspection to assess the watershed control program and disinfection treatment process. Either the State or a party approved by the State must conduct the on-site inspection. The inspection must be conducted by competent individuals such as sanitary and civil engineers, sanitarians, or technicians who have experience and knowledge about the operation and maintenance of a public water system, and who have a sound understanding of public health principles and waterborne di seases. A report of the on-site ins pection summarizing all findings must be prepared every year. The on-site inspecti on must indicate to the State's satisfaction that the watershed control program and disinfection treatm ent process are adequately designed and maintained. The on-site inspection must include: 

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...(i) A review of the effectiveness of the watershed control program;
(ii) A review of the physical condition of the source intake and how well it is protected;
(iii) A review of the system's equipment maintenance program to ensure there is low probability for failure of the disinfection process;
(iv) An inspection of the disinfecti on equipment for physical deterioration;

(v) A review of operating procedures;
(vi) A review of data records to ensure that all required tests are being conducted and recorded and disinfection is effect ively practiced; and
(vii) Identification of any improvements which are needed in the equipment, system maintenance and operation, or data collection.
(4) The public water system must not have been identified as a source of a waterborne disease outbreak, or if it has been so identified, the syst em must have been modified sufficiently to prevent another such occurrence, as determined by the State.

(5) The public water system must comply with the maximum contaminant level (MCL) for total coliforms in §141.63 at least 11 months of the 12 previous mo nths that the system served water to the public, on an ongoing basis, unless the State determines that failure to meet this requirement was not caused by a deficiency in treatment of the source water.

(6) The public water system must comply with the requirements for trihalomethanes in §§141.12 and 141.30 until December 31, 2001. After December 31, 2001, the system must comply with the requirements for total trihalomethanes, haloacetic ac ids (five), bromate, chlorite, chlorine, chloramines, and chlorine dioxide in subpart L of this part.
(c) Treatment technique violations. (1) A system that (i) fails to meet any one of the criteria in paragraphs (a) and (b) of this section and/or which th e State has determined that filtration is required, in writing pursuant to §1412(b)(7)(C)(iii), and (ii) fails to install filtration by the date specified in the introductory paragraph of this section is in viol ation of a treatment technique requirement.
(2) A system that has not installed filtration is in violation of a treatment technique requirement if:
(i) The turbidity level (measured as specified in §141.74(a)(1) and (b)(2)) in a representative sample of the source water immediately prior to the first or only point of disinfection application exceeds 5 NTU; or

(ii) The system is identified as a source of a waterborne disease outbreak.

[54 FR 27527, June 29, 1989, as amended at 63 FR 69516, Dec. 16, 1998; 66 FR 3776, Jan. 16, 2001; 69 FR 38855, June 29, 2004]


### § 141.72 Disinfection.

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Apublic water system that uses a surface water source and does not provide filtration treatment must provide the disinfection treatmen t specified in paragraph (a) of this section beginning December 30, 1991, unless the State determines that filt ration is required in writing pursuant to §1412 (b)(7)(C)(iii). A public water system that uses a ground water sour ce under the direct influence of surface water and does not provide filtration treatment must provide disinfection treatment specified in paragraph (a) of this section beginning December 30, 1991, or 18 months after the State determines that the ground water source is under the influence of surface water, whichever is later, unless the State has determined that filtration is required in writing pursuant to §1412(b)(7)(C)(iii). If the State has determined that filtration is required, the system must comply with any interim disinfection requirements the State deems necessary before filtration is installed. A syste m that uses a surface water source that provides filtration treatment must provide the disinfection treatment specified in paragraph (b) of this section beginnng June 29, 1993, or beginning when filtration is installed, whic hever is later. A system that uses a ground water source under the direct influence of surface water and provides filtration treatment must provide disinfection treatment as specified in paragraph (b) of this section by June 29, 1993, or beginning when filtration is installed, whichever is later. Failure to meet any requirement of this section after the applicable date specified in this introductory paragraph is a treatment technique violation.
(a) Disinfection requirements for public water systems that do not provide filtration. Each public water system that does not provide f iltration treatment must provide di sinfection treatment as follows:
(1) The disinfection treatment must be sufficient to ensure at least 99.9 percen t (3-log) inactivation of Giardia lamblia cysts and 99.99 percent (4-log) inactivation of viruses, every day the system serves water to the public, except any one day each month. Each day a system serves water to the public, the public water system must calculate the CT value(s) from the system's treatment parameters, using the procedure specified in §141.74(b)(3), and determine whether this value(s) is sufficient to achieve the specified inactivation rates for Giardia lamblia cysts and viruses. If a system uses a disinfectant other than chlorine, the system may demonstrate to the State, through the use of a State-approved protocol for on-site disinfection challeng e studies or other information satisfactory to the State, that CT 99.9 values other than those specified in tables 2.1 and 3.1 in §141.74(b)(3) or other operational parameters are adequate to demonstrate that the system is achieving mi nimum inactivation rates required by paragraph (a)(1) of this section.

(2) The disinfection system must have either (i) redundant components, including an auxiliary power supply with automatic start-up and alarm to ensu re that disinfectant application is maintained continuously while water is being delivered to the distri bution system, or (ii) automatic shut-off of delivery of water to the distribution system whenever there is less than 0.2 mg/l of residual disinfectant concentration in the water. If the State determines that automatic shut-off woul d cause unreasonable risk to health or interfere with fire protection, the system must comply with paragraph (a)(2)(i) of this section.
(3) The residual disinfectant concentration in the wate r entering the distribution system, measured as specified in §141.74 (a)(2) and (b)(5), cannot be less than 0.2 mg/l for more than 4 hours.

(4)(i) The residual disinfectant conc entration in the distribution system, measured as total chlorine, 

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...combined chlorine, or chlorine dioxide, as specified in §141.74 (a)(2) and (b)(6), cannot be undetectable in more than 5 percent of the samples each month, for any two consecutive months that the system serves water to the public. Water in the distribution system with a heterotrophic bacteria concentration less than or equal to 500/ml, measured as heterotrophic plate count (HPC) as specified in §141.74(a)(1), is deemed to have a detectable disinfectant residual for purposes of determining compliance with this requirement. Thus, the value “V” in the following formula cannot exceed 5 percent in one month, for any two consecutive months.



### where:

a=number of instances where the residual disinfectant concentration is measured;

b=number of instances where the residual disinfectant concentration is not measured but heterotrophic bacteria plate count (HPC) is measured;

c=number of instances where the residual disinfectant concentration is measured but not detected and no HPC is measured;

d=number of instances where the residual disinfectant concentration is measured but not detected and where the HPC is >500/ml; and

e=number of instances where the residual disinfectant concentration is not measured and HPC is >500/ml.

(ii) If the State determines, based on si te-specific considerations, that a system has no means for having a sample transported and analyzed for HPC by a cert ified laboratory under the requisite time and temperature conditions specified by §141.74(a)(1) and that the system is providing adequate disinfection in the distribution system, the requirements of par agraph (a)(4)(i) of this section do not apply to that system.
(b) Disinfection requirements for public wa ter systems which provide filtration. Each public water system that provides filtration treatment must provide disinfection treatment as follows.

(1) The disinfection treatment must be sufficient to ensure that the total treatment processes of that system achieve at least 99.9 percent (3 -log) inactivation and/or removal of Giardia lamblia cysts and at least 99.99 percent (4-log) inacti vation and/or removal of viruses, as determined by the State.
(2) The residual disinfectant concentration in the wate r entering the distribution system, measured as specified in §141.74 (a)(2) and (c)(2), cannot be less than 0.2 mg/l for more than 4 hours.
(3)(i) The residual disinfectant conc entration in the distribution system, measured as total chlorine, combined chlorine, or chlorine dioxide, as specified in §141.74 (a)(2) and (c)(3), cannot be undetectable in more than 5 percent of the samples each month, for any two consecutive months that the system serves water to the public. Water in the distribution system with a heterotrophic bacteria concentration less than or equal to 500/ml, measured as heterotrophic plate count (HPC) as specified in §141.74(a)(1), is deemed to have a detectable disinfectant residual for purposes of determining compliance with this requirement. Thus, the value “V” in the following formula cannot exceed 5 percent in one month, for any two consecutive months.



### where:

a=number of instances where the residual disinfectant concentration is measured;

b=number of instances where the residual disinfectant concentration is not measured but heterotrophic bacteria plate count (HPC) is measured;

c=number of instances where the residual disinfectant concentration is measured but not detected and no HPC is measured;

d=number of instances where no residual disinfectant concentration is detected and where the HPC is >500/ml; and

e=number of instances where the residual disinfectant concentration is not measured and HPC is >500/ml.

(ii) If the State determines, based on si te-specific considerations, that a system has no means for having a sample transported and analyzed for HPC by a cert ified laboratory under the requisite time and temperature conditions specified in §141.74(a)(1) and that the system is providing adequate disinfection in the distribution system, the requirements of paragraph (b)(3)(i) of this section do not apply.

[54 FR 27527, June 29, 1989, as amended at 69 FR 38855, June 29, 2004]


### § 141.73 Filtration.

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Apublic water system that uses a surface water source or a ground water source under the direct influence of surface water, and does not meet all of the criteria in §141.71 (a) and (b) for avoiding filtration, must provide treatment consis ting of both disinfection, as specif ied in §141.72(b), and filtration treatment which complies with the requirements of paragraph (a), (b), (c), (d), or (e) of this section by June 29, 1993, or within 18 months of the failure to meet any one of the criteria for avoiding filtration in §141.71 (a) and (b), whichever is later. Failure to meet any requirement of this section after the date 

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...specified in this introductory paragraph is a treatment technique violation.
(a) Conventional filtration treatment or direct filtration. (1) For systems using conv entional filtration or direct filtration, the turbidity level of representative samples of a system's filtered water must be less than or equal to 0.5 NTU in at least 95 percent of the measurements taken each month, measured as specified in §141.74 (a)(1) and (c)(1), except that if the State determines that the system is capable of achieving at least 99.9 percent re moval and/or inactivation of Giardia lamblia cysts at some turbidity level higher than 0.5 NTU in at least 95 percent of the measurements taken each month, the State may substitute this higher turbidity limit for that system. However, in no case may the State approve a turbidity limit that allows more than 1 NTU in more than 5 percent of the samples taken each month, measured as specified in §141.74 (a)(1) and (c)(1).

(2) The turbidity level of representative samples of a system's filtered water must at no time exceed 5 NTU, measured as specified in §141.74 (a)(1) and (c)(1).

(3) Beginning January 1, 2002, systems serving at least 10,000 people must meet the turbidity requirements in §141.173(a).
(4) Beginning January 1, 2005, systems serving fewer than 10,000 people must meet the turbidity requirements in §§141.550 through 141.553.
(b) Slow sand filtration. (1) For systems using slow sand filtration, the turbidity level of representative samples of a system's filtered water must be less than or equal to 1 NTU in at least 95 percent of the measurements taken each month, measured as specif ied in §141.74 (a)(1) and (c)(1), except that if the State determines there is no significant interference with disinfection at a higher turbidity level, the State may substitute this higher turbidity limit for that system.
(2) The turbidity level of representative samples of a system's filtered water must at no time exceed 5 NTU, measured as specified in §141.74 (a)(1) and (c)(1).

(c) Diatomaceous earth filtration. (1) For systems using diatomaceous earth filtration, the turbidity level of representative samples of a system's filtered water must be less than or equal to 1 NTU in at least 95 percent of the measurements taken each month, meas ured as specified in §141.74 (a)(1) and (c)(1).

(2) The turbidity level of representative samples of a system's filtered water must at no time exceed 5 NTU, measured as specified in §141.74 (a)(1) and (c)(1).
(d) Other filtration technologies. A public water system may use a filtration technology not listed in paragraphs (a) through (c) of this section if it demonstrates to the State, using pilot plant studies or other means, that the alternative filtration technology, in co mbination with disinfection treatment that meets the requirements of §141.72(b), consis tently achieves 99.9 percent re moval and/or inactivation of Giardia lamblia cysts and 99.99 percent removal and/or inactivati on of viruses. For a system that makes this demonstration, the requirements of paragraph (b) of this section apply. Beginning January 1, 2002, systems serving at least 10,000 people must meet the requirements for other filtration technologies in §141.173(b). Beginning January 14, 2005, systems serving fewer than 10,000 people must meet the requirements for other filtration tech nologies in §141.550 through 141.553.

[54 FR 27527, June 29, 1989, as amended at 63 FR 69516, Dec. 16, 1998; 66 FR 3776, Jan. 16, 2001; 67 FR 1836, Jan. 14, 2002; 69 FR 38855, June 29, 2004]


### § 141.74 Analytical and monitoring requirements.

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(a) Analytical requirements. Only the analytical method(s) specif ied in this paragraph, or otherwise approved by EPA, may be used to demonstrate compliance with §§141.71, 141.72 and 141.73. Measurements for pH, turbidity, temperature and re sidual disinfectant concent rations must be conducted by a person approved by the State. Measurement for to tal coliforms, fecal coliforms and HPC must be conducted by a laboratory certified by the State or EPA to do such analysis. Until laboratory certification criteria are developed for the analysis of fecal coliforms and HPC, any laboratory certified for total coliforms analysis by the State or EPA is deemed certified for fecal coliforms and HP C analysis. The following procedures shall be conducted in accord ance with the publications listed in the following section. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the methods published in Standard Methods for the Examination of Water and Wastewater may be obtained from the American Public Health Association et al., 1015 Fifteenth Street, NW., Washington, DC 20005; copies of the Minimal Medium ONPG-MUG Method as set forth in the articl e “National Field Evaluation of a Defined Substrate Method for the Simultaneous Enumeration of Total Coliforms and Esherichia coli from Drinking Water: Comparison with the Standard Multiple Tube Fermentation Method” (Edberg et al.), Applied and Environmental Microbiology, Volume 54, pp. 1595–1601, June 1988 (as amended under Erratum, A pplied and Environmental Microbiology, Volume 54, p. 3197, December, 1988), may be obtained from the American Water Works Association Research Foundation, 6666 West Quincy Avenue, Denver, Colorado, 80235; and copies of the Indigo Method as set forth in the article “Determination of Ozone in Water by the Indigo Method” (Bader and Hoigne), may be obtained from Ozone Science & Engineering, Pergamon Press Ltd., Fairview Park, Elmsford, New Yo rk 10523. Copies may be inspected at the U.S. Environmental Protection Agency, Room EB15, 401 M St., SW., Washington, DC 20460 or at the National Archives and Records Administration (NARA). For information on the availa bility of this material at NARA, call 202–741–6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
(1) Public water systems must conduct analysis of pH and temperature in accordance with one of the methods listed at §141.23(k)(1). Public water systems must conduct analysis of total coliforms, fecal coliforms, heterotrophic bacteria, and turbidity in acco rdance with one of the following analytical methods or one of the alternative methods listed in appendix A to subpart C of this part and by using analytical test procedures contained in Technical Notes on Drinking Water Methods, EPA–600/R–94–173, October 1994. This document is available from the Nati onal Service Center for Environmental Publications (NSCEP), P.O. Box 42419, Cincinnati, OH 45242–0419 or http://www.epa.gov/nscep/

. 

## Organism Methodology Citation 1


## Total Coliform 2 

## Total Coliform Fermentation Technique 3,4,5 

## 9221 A, B, C Total Coliform Membrane Filter 9222 A, B, C 

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...The procedures shall be done in accordance with the documents listed below. The incorporation by reference of the following documents listed in footnotes 1, 6, 7 and 9–12 was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the documents may be obtained from the sources listed below. Infor mation regarding obtaining these documents can be obtained from the Safe Drinking Water Hotline at 800–426–4791. Documents may be inspected at EPA's Drinking Water Docket, 1301 Constitution Av enue, NW., EPA West, Room B102, Washington DC 20460 (Telephone: 202–566–2426); or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202–741–6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

1 Except where noted, all methods refer to Standard Methods for the Examination of Water and Wastewater, 18th edition (1992), 19th edition (1995), or 20th edition (1998), American Public Health Association, 1015 Fifteenth Street, NW., Washington , DC 20005. The cited methods published in any of these three editions may be used. In addition, the following online versions may also be used: 2130 B– 01, 9215 B–00, 9221 A, B, C, E–99, 9222 A, B, C, D–97, and 9223 B–97. Standard Methods Online are available at http://www.standardmethods.org. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only Online versions that may be used.

2 The time from sample collection to initiation of anal ysis may not exceed 8 hours. Systems must hold samples below 10 deg. C during transit.

3 Lactose broth, as commercially available, may be used in lieu of lauryl tryptose broth, if the system conducts at least 25 parallel tests between this medium and lauryl tryptose broth using the water normally tested, and this comparison demonstrates th at the false-positive rate and false-negative rate for total coliform, using lactose broth, is less than 10 percent.

4 Media should cover inverted tubes at least on e-half to two-thirds after the sample is added.

5 No requirement exists to run the completed phase on 10 percent of all total coliform-positive confirmed tubes.

6 MI agar also may be used. Preparation and use of MI a gar is set forth in the article, “New medium for the simultaneous detection of total coliform and Escherichia coli in water” by Brenner, K.P., et. al., 1993, A ppl. Environ. Microbiol. 59:3534–3544. Also available from the Office of Water Resource Center (RC– 4100T), 1200 Pennsylvania Avenue, NW., Washington DC 20460, EPA/600/J–99/225. Verification of colonies is not required.

7 The ONPG-MUG Test is also known as the Autoanalysis Colilert System.

8 A–1 broth may be held up to 7 days in a tightly closed screw cap tube at 4 °C.

9 “Methods for the Determination of Inorganic Substances in Environmental Samples”, EPA/600/R– 93/100, August 1993. Available at NTIS, PB94–121811.

10 GLI Method 2, “Turbidity,” November 2, 1992, Grea t Lakes Instruments, Inc., 8855 North 55th Street, Milwaukee, WI 53223.

11 A description of the SimPlate method, “IDEXX SimPl ate TM HPC Test Method for Heterotrophs in Water,” November 2000, can be obtained from IDEXX Laboratories, Inc., 1 IDEXX Drive, Westbrook, ME 04092, telephone (800) 321–0207.

12 A description of the Hach FilterTrak M ethod 10133, “Determination of Turbidity by Laser Nephelometry,” January 2000, Revision 2.0, can be obtained from; Hach Co., P.O. Box 389, Loveland, CO 80539–0389, telephone: 800–227–4224.

13 Styrene divinyl benzene beads (e.g., AMCO-AEPA–1 or equivalent) and stabilized formazin (e.g., Hach StablCal TM or equivalent) are acceptab le substitutes for formazin.

(2) Public water systems must measure residual disinfectant concentrations with one of the analytical methods in the following table or one of the alternative methods listed in appendix A to subpart C of this part. If approved by the State, residual disinfecta nt concentrations for free chlorine and combined chlorine also may be measured by using DPD colori metric test kits. In addition States may approve the use of the ITS free chlorine test strip for the dete rmination of free chlorine. Use of the test strips is described in Method D99–003, “Free Chlorine Species (HOCl − and OCl − ) by Test Strip,” Revision 3.0, November 21, 2003, available from Industrial Te st Systems, Inc., 1875 Langston St., Rock Hill, SC 29730. Free and total chlorine residuals may be measured continuously by adapting a specified chlorine residual method for use with a continuous monitoring in strument provided the chemistry, accuracy, and precision remain the same. Instruments used for c ontinuous monitoring must be calibrated with a grab sample measurement at least every five days, or with a protocol approved by the State. 

## Technique 6


## ONPG-MUG Test 7 

## 9223
Fecal Coliforms 2 

## Fecal Coliform Procedure 8 

## 9221 E Fecal Coliform Filter Procedure 9222 D Heterotrophic bacteria 2 

## Pour Plate Method 9215 B

SimPlate 11 

## Turbidity 13 

## Nephelometric Method 2130 B Nephelometric Method 180.1 9 

## Great Lakes Instruments Method 2 10 

## Hach FilterTrak 10133 12 

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...1 All the listed methods are contained in the 18th, 19th, and 20th editions of Standard Methods for the Examination of Water and Wastewater, 1992, 1995, and 1998; the cited methods published in any of these three editions may be used.

2 Standard Methods Online are available at http://www.standardmethods.org. The year in which each method was approved by the Standard Methods Commi ttee is designated by the last two digits in the method number. The methods listed are the only Online versions that may be used.

3 Annual Book of ASTM Standards, Vol. 11.01, 2004 ; ASTM International; any year containing the cited version of the method may be used. Copies of this method may be obtained from ASTM International, 100 Barr Harbor Drive, P.O. Box C700 West Conshohocken, PA 19428–2959.

4 EPA Method 327.0, Revision 1.1, “Determination of Chlori ne Dioxide and Chlorite Ion in Drinking Water Using Lissamine Green B and Horseradish Peroxidas e with Detection by Visi ble Spectrophotometry,” USEPA, May 2005, EPA 815–R–05–008. Available online at http://www.epa.gov/safewater/m ethods/sourcalt.html.

(b) Monitoring requirements for system s that do not provide filtration. A public water system that uses a surface water source and does not provide filtration treatment must begin monitoring, as specified in this paragraph (b), beginning December 31, 1990, unless the State has determined that filtration is required in writing pursuant to §1412(b)(7)(C)(iii), in which case the State may specify alternative monitoring requirements, as appropriate, until filtration is in place. A public water system that uses a ground water source under the direct influence of surface water and does not provide filtration treatment must begin monitoring as specified in this paragraph (b) begi nning December 31, 1990, or 6 months after the State determines that the ground water source is under the direct influence of surface water, whichever is later, unless the State has determined that filtration is required in writing pursuant to §1412(b)(7)(C)(iii), in which case the State may specify alternative monito ring requirements, as appropriate, until filtration is in place.
(1) Fecal coliform or total coliform density meas urements as required by §141.71(a)(1) must be performed on representative source water samples immediately prior to the first or only point of disinfectant application. The system must sample for fecal or total coliforms at the following minimum frequency each week the system serves water to the public:

1 Must be taken on separate days.

A lso, one fecal or total coliform density measurement must be made every day the system serves water to the public and the turbidity of the source water exceeds 1 NTU (these samples count towards the weekly coliform sampling requirement) unless the State determines that the system, for logistical



## Residual Methodology SM 1 

## SM Online 2 

## Other Free Chlorine Amperometric Titration 4500–Cl D 4500–Cl D–00 D1253–03 3



## DPD Ferrous Titrimetric 4500–Cl F 4500–Cl F–00 DPD Colorimetric 4500–Cl G 4500–Cl G–00 Syringaldazine (FACTS) 4500–Cl H 4500–Cl H–00 Total Chlorine Amperometric Titration 4500–Cl D 4500–Cl D–00 D1253–03 3


## Amperometric Titration (low level measurement) 4500–Cl E 4500–Cl E–00 DPD Ferrous Titrimetric 4500–Cl F 4500–Cl F–00 DPD Colorimetric 4500–Cl G 4500–Cl G–00 Iodometric Electrode 4500–Cl I 4500–Cl I– 00 Chlorine Dioxide Amperometric Titration 4500– ClO2 C 4500–ClO2 C–00 DPD Method 4500– ClO2 D Amperometric Titration 4500– ClO2 E 4500–ClO2 E–00 Spectrophotometric 327.0, Revision 1.1 4 

## Ozone Indigo Method 4500– O3 B 4500–O3 B–97

System size (persons served) Samples/week 1


## ≤ 500 1 501 to 3,300 2 3,301 to 10,000 3 10,001 to 25,000 4 >25,000 5 

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...reasons outside the system's control, cannot have the sample analyzed within 30 hours of collection.
(2) Turbidity measurements as required by §141.71( a)(2) must be performed on representative grab samples of source water immediately prior to the fi rst or only point of disinfec tant application every four hours (or more frequently) that the system serves water to the public. A public water system may substitute continuous turbidity moni toring for grab sample monitoring if it validates the continuous measurement for accuracy on a regular basi s using a protocol approved by the State.
(3) The total inactivati on ratio for each day that the system is in operation must be determined based on the CT 99.9 values in tables 1.1–1.6, 2.1, and 3.1 of this section, as appropriate. The parameters necessary to determine the total inactivati on ratio must be monitored as follows:

(i) The temperature of the disinfected water must be measured at least once per day at each residual disinfectant concentrati on sampling point.
(ii) If the system uses chlorine, the pH of the di sinfected water must be measured at least once per day at each chlorine residual disinfectan t concentration sampling point.
(iii) The disinfectant contact time (s) (“T”) must be determined for each day during peak hourly flow.
(iv) The residual disinfectant conc entration(s) (“C”) of the water before or at the first customer must be measured each day during peak hourly flow.

(v) If a system uses a di sinfectant other than chlorine, the system may demonstrate to the State, through the use of a State-approved protocol for on-site disinfection challenge studies or other information satisfactory to the State, that CT 99.9 values other than those specified in tables 2.1 and 3.1 in this section other operational parameters are adequate to demonstrate that the system is achieving the minimum inactivation rates requi red by §141.72(a)(1).

Table 1.1—CT Values (CT 99.9 ) for 99.9 Percent Inactivation of Giardia Lamblia Cysts by Free Chlorine at 0.5 °C or Lower 1

1 These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by linea r interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolati on. If no interpolation is used, use the CT 99.9 value at the lower temperature and at the higher pH.

Table 1.2—CT Values (CT 99.9 ) for 99.9 Percent Inactivation of Giardia Lamblia Cysts by Free Chlorine at 5.0 °C 1 

## Residual (mg/l) pH ≤ 6.0 6.5 7.0 7.5 8.0 8.5 ≤ 9.0 ≤ 0.4 137 163 195 237 277 329 390 0.6 141 168 200 239 286 342 407 0.8 145 172 205 246 295 354 422 1.0 148 176 210 253 304 365 437 1.2 152 180 215 259 313 376 451 1.4 155 184 221 266 321 387 464 1.6 157 189 226 273 329 397 477 1.8 162 193 231 279 338 407 489 2.0 165 197 236 286 346 417 500 2.2 169 201 242 297 353 426 511 2.4 172 205 247 298 361 435 522 2.6 175 209 252 304 368 444 533 2.8 178 213 257 310 375 452 543 3.0 181 217 261 316 382 460 552

Free residual (mg/l) pH ≤ 6.0 6.5 7.0 7.5 8.0 8.5 ≤ 9.0 ≤ 0.4 97 117 139 166 198 236 279 0.6 100 120 143 171 204 244 291 0.8 103 122 146 175 210 252 301 1.0 105 125 149 179 216 260 312 1.2 107 127 152 183 221 267 320 1.4 109 130 155 187 227 274 329 1.6 111 132 158 192 232 281 337 1.8 114 135 162 196 238 287 345 2.0 116 138 165 200 243 294 353 2.2 118 140 169 204 248 300 361 2.4 120 143 172 209 253 306 368 2.6 122 146 175 213 258 312 375 2.8 124 148 178 217 263 318 382 3.0 126 151 182 221 268 324 389 

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...1 These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by linea r interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolati on. If no interpolation is used, use the CT 99.9 value at the lower temperature, and at the higher pH.

Table 1.3—CT Values (CT 99.9 ) for 99.9 Percent Inactivation of Giardia Lamblia Cysts by Free Chlorine at 10.0 °C 1

1 These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by linea r interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolati on. If no interpolation is used, use the CT 99.9 value at the lower temperature, and at the higher pH.

Table 1.4—CT Values (CT 99.9 ) for 99.9 Percent Inactivation of Giardia Lamblia Cysts by Free Chlorine at 15.0 °C 1

1 These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by linea r interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolati on. If no interpolation is used, use the CT 99.9 value at the lower temperature, and at the higher pH.

Table 1.5—CT Values (CT 99.9 ) for 99.9 Percent Inactivation of Giardia Lamblia Cysts by Free Chlorine at 20°C 1 

## Free residual (mg/l) pH ≤ 6.0 6.5 7.0 7.5 8.0 8.5 ≤ 9.0 ≤ 0.4 73 88 104 125 149 177 209 0.6 75 90 107 128 153 183 218 0.8 78 92 110 131 158 189 226 1.0 79 94 112 134 162 195 234 1.2 80 95 114 137 166 200 240 1.4 82 98 116 140 170 206 247 1.6 83 99 119 144 174 211 253 1.8 86 101 122 147 179 215 259 2.0 87 104 124 150 182 221 265 2.2 89 105 127 153 186 225 271 2.4 90 107 129 157 190 230 276 2.6 92 110 131 160 194 234 281 2.8 93 111 134 163 197 239 287 3.0 95 113 137 166 201 243 292

Free residual (mg/l) pH ≤ 6.0 6.5 7.0 7.5 8.0 8.5 ≤ 9.0 ≤ 0.4 49 59 70 83 99 118 140 0.6 50 60 72 86 102 122 146 0.8 52 61 73 88 105 126 151 1.0 53 63 75 90 108 130 156 1.2 54 64 76 92 111 134 160 1.4 55 65 78 94 114 137 165 1.6 56 66 79 96 116 141 169 1.8 57 68 81 98 119 144 173 2.0 58 69 83 100 122 147 177 2.2 59 70 85 102 124 150 181 2.4 60 72 86 105 127 153 184 2.6 61 73 88 107 129 156 188 2.8 62 74 89 109 132 159 191 3.0 63 76 91 111 134 162 195

Free residual (mg/l) pH ≤6.0 6.5 7.0 7.5 8.0 8.5 ≤9.0 ≤ 0.4 36 44 52 62 74 89 105 0.6 38 45 54 64 77 92 109 0.8 39 46 55 66 79 95 113 1.0 39 47 56 67 81 98 117 1.2 40 48 57 69 83 100 120 1.4 41 49 58 70 85 103 123 1.6 42 50 59 72 87 105 126 1.8 43 51 61 74 89 108 129 

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...1 These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by linea r interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolati on. If no interpolation is used, use the CT 99.9 value at the lower temperature, and at the higher pH.

Table 1.6—CT Values (CT 99.9 ) for 99.9 Percent Inactivation of Giardia Lamblia Cysts by Free Chlorine at 25°C 1 and Higher

1 These CT values achieve greater than a 99.99 percent inactivation of viruses. CT values between the indicated pH values may be determined by linea r interpolation. CT values between the indicated temperatures of different tables may be determined by linear interpolati on. If no interpolation is used, use the CT 99.9 value at the lower temperature, and at the higher pH.

Table 2.1—CT Values (CT 99.9 ) for 99.9 Percent Inactivation of Giardia Lamblia Cysts by Chlorine Dioxide and Ozone 1

1 These CT values achieve greater than 99.99 percent inactivation of viruses. CT values between the indicated temperatures may be determined by linear interpolation. If no interpolation is used, use the CT 99.9 value at the lower temperature for determining CT 99.9 values between indicated temperatures.

Table 3.1—CT Values (CT 99.9 ) for 99.9 Percent Inactivation of Giardia Lamblia Cysts By Chloramines 1

1 These values are for pH values of 6 to 9. These CT values may be assumed to achieve greater than 99.99 percent inactivation of viruses only if chlorine is added and mixed in the water prior to the addition of ammonia. If this condition is not met, the system must demonstrate, based on on-site studies or other information, as approved by the State, that the system is achieving at least 99.99 percent inactivation of viruses. CT values between the indicated temperatur es may be determined by linear interpolation. If no interpolation is used, use the CT 99.9 value at the lower temperature for determining CT 99.9 values between indicated temperatures.
(4) The total inactivati on ratio must be calculated as follows:

(i) If the system uses only one po int of disinfectant application, th e system may determine the total inactivation ratio based on either of the following two methods:
(A) One inactivation ratio (CTcalc/CT 99.9 ) is determined before or at the first customer during peak hourly flow and if the CTcalc/CT 99.9 ≥ 1.0, the 99.9 percent Giardia lamblia inactivation requirement has been achieved; or 

## 2.0 44 52 62 75 91 110 132 2.2 44 53 63 77 93 113 135 2.4 45 54 65 78 95 115 138 2.6 46 55 66 80 97 117 141 2.8 47 56 67 81 99 119 143 3.0 47 57 68 83 101 122 146

Free residual (mg/l) pH ≤6.0 6.5 7.0 7.5 8.0 8.5 ≤9.0 ≤ 0.4 24 29 35 42 50 59 70 0.6 25 30 36 43 51 61 73 0.8 26 31 37 44 53 63 75 1.0 26 31 37 45 54 65 78 1.2 27 32 38 46 55 67 80 1.4 27 33 39 47 57 69 82 1.6 28 33 40 48 58 70 84 1.8 29 34 41 49 60 72 86 2.0 29 35 41 50 61 74 88 2.2 30 35 42 51 62 75 90 2.4 30 36 43 52 63 77 92 2.6 31 37 44 53 65 78 94 2.8 31 37 45 54 66 80 96 3.0 32 38 46 55 67 81 97

Temperature < 1°C 5°C 10°C 15°C 20°C ≥25°C Chlorine dioxide 63 26 23 19 15 11 Ozone 2.9 1.9 1.4 0.95 0.72 0.48

Temperature < 1 °C 5 °C 10 °C 15 °C 20 °C 25 °C 3,800 2,200 1,850 1,500 1,100 750 

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...(B) Successive CTcalc/CT 99.9 values, representing sequential in activation rati os, are determined between the point of disinfectant application and a point before or at the first customer during peak hourly flow. Under this alternativ e, the following method must be used to calculate the total inactivation ratio:

lamblia inactivation requirem ent has been achieved.
(ii) If the system uses more than one point of disinfectant application before or at the first customer, the system must determine the CT value of each disinfecti on sequence immediately prior to the next point of disinfectant application during peakhourly flow. The CTcalc/CT 99.9 value of each sequence and

must be calculated using the method in paragraph (b)(4)(i )(B) of this section to determine if the system is in compliance with §141.72(a).
(iii) Although not required, the total pe rcent inactivation for a system with one or more points of residual disinfectant concentration monitoring may be calc ulated by solving the following equation:

(5) The residual disinfectant concentration of the water entering the distribution system must be monitored continuously, and the lowest value must be recorded each day, except that if there is a failure in the continuous monitoring equipment, grab samp ling every 4 hours may be conducted in lieu of continuous monitoring, but for no more than 5 worki ng days following the failure of the equipment, and systems serving 3,300 or fewer persons may take grab samples in lieu of providing continuous monitoring on an ongoing basis at the frequencies prescribed below:

1 The day's samples cannot be taken at the same time . The sampling intervals are subject to State review and approval.
If at any time the residual disinfectant concentration falls below 0.2 mg/l in a system using grab sampling in lieu of continuous monitoring, the system must take a grab sample every 4 hours until the residual concentration is equal to or greater than 0.2 mg/l.
(6)(i) The residual disinfectant conc entration must be measured at least at the same points in the distribution system and at the same time as total co liforms are sampled, as specified in §141.21, except that the State may allow a public water system whic h uses both a surface water source or a ground water source under direct influence of surface water , and a ground water source, to take disinfectant residual samples at points other than the total coliform sampling points if the State determines that such points are more representative of treated (disin fected) water quality within the distribution system. Heterotrophic bacteria, measured as heterotrophic plate count (HPC) as specified in paragraph (a)(3) of this section, may be measured in lieu of residual disinfectant concentration.
(ii) If the State determines, based on si te-specific considerations, that a system has no means for having a sample transported and analyzed for HPC by a cert ified laboratory under the requisite time and temperature conditions specified by paragraph (a)(1) of this section and that the system is providing adequate disinfection in the distributi on system, the requirements of paragraph (b)(6)(i) of this section do not apply to that system.
(c) Monitoring requirements for systems using filtration treatment. A public water system that uses a surface water source or a ground water source under the influence of surface water and provides filtration treatment must monitor in accordance with this paragraph (c) beginning June 29, 1993, or when filtration is installed, whichever is later.
(1) Turbidity measurements as required by §141.73 must be performed on representative samples of the system's filtered water every four hours (or more frequently) that the system serves water to the public. Apublic water system may substitute continuous turbidity monitoring for grab sample monitoring if it validates the continuous measurement for accuracy on a regular basis us ing a protocol approved by the State. For any systems using slow sand filtration or filtration treatment other than conventional treatment, direct filtration, or diatomaceous earth fi ltration, the State may reduce the sampling frequency to once per day if it determines that less frequent monitor ing is sufficient to indicate effective filtration performance. For systems serving 500 or fewer person s, the State may reduce the turbidity sampling frequency to once per day, regardless of the type of f iltration treatment used, if the State determines that less frequent monitoring is sufficient to indicate effective filtration performance. 

## System size by population Samples/day 1 

## <500 1 501 to 1,000 2 1,001 to 2,500 3 2,501 to 3,300 4 

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...(2) The residual disinfectant concentration of the water entering the distribution system must be monitored continuously, and the lowest value must be recorded each day, except that if there is a failure in the continuous monitoring equipment, grab samp ling every 4 hours may be conducted in lieu of continuous monitoring, but for no more than 5 worki ng days following the failure of the equipment, and systems serving 3,300 or fewer persons may take grab samples in lieu of providing continuous monitoring on an ongoing basis at the frequencies each day prescribed below:

1 The day's samples cannot be taken at the same time . The sampling intervals are subject to State review and approval.
If at any time the residual disinfectant concentration falls below 0.2 mg/l in a system using grab sampling in lieu of continuous monitoring, the system must take a grab sample every 4 hours until the residual disinfectant concentration is equal to or greater than 0.2 mg/l.
(3)(i) The residual disinfectant conc entration must be measured at least at the same points in the distribution system and at the same time as total co liforms are sampled, as specified in §141.21, except that the State may allow a public water system whic h uses both a surface water source or a ground water source under direct influence of surface water, and a ground water source to take disinfectant residual samples at points other than the total coliform sampling points if the State determines that such points are more representative of treated (disin fected) water quality within the distribution system. Heterotrophic bacteria, measured as heterotrophic plate count (HPC) as specified in paragraph (a)(1) of this section, may be measured in lieu of residual disinfectant concentration.
(ii) If the State determines, based on si te-specific considerations, that a system has no means for having a sample transported and analyzed for HPC by a cert ified laboratory under the requisite time and temperature conditions specified by paragraph (a)(1) of this section and that the system is providing adequate disinfection in the distri bution system, the requirements of para graph (c)(3)(i) of this section do not apply to that system.

[54 FR 27527, June 29, 1989, as amended at 59 FR 62470, Dec. 5, 1994; 60 FR 34086, June 29, 1995; 64 FR 67465, Dec. 1, 1999; 67 FR 65252, Oct. 23, 2002; 67 FR 65901, Oct. 29, 2002; 69 FR 38856, June 29, 2004; 72 FR 11247, Mar. 12, 2007; 74 FR 30958, June 29, 2009]


### § 141.75 Reporting and recordkeeping requirements.

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(a) A public water system that uses a surface water source and does not provide filtration treatment must report monthly to the State the information specified in this paragraph (a) beginning December 31, 1990, unless the State has determined that filtration is required in writing pursuant to section 1412(b)(7) (C)(iii), in which case the State may specify alte rnative reporting requirements, as appropriate, until filtration is in place. A public water system that us es a ground water source under the direct influence of surface water and does not provide filtration treatment must report monthly to the State the information specified in this paragraph (a) beginning December 31, 1990, or 6 months after the State determines that the ground water source is under the direct influence of surface water, whichever is later, unless the State has determined that filtration is required in writing pursuant to §1412(b)(7)(C)(iii), in which case the State may specify alternative reporting requirements , as appropriate, until filtration is in place.

(1) Source water quality information must be repo rted to the State within 10 days after the end of each month the system serves water to the public. Information that must be reported includes:
(i) The cumulative number of months for which results are reported.
(ii) The number of fecal and/or total coliform sample s, whichever are analyzed during the month (if a system monitors for both, only fecal coliforms must be reported), the dates of sample collection, and the dates when the turbidity level exceeded 1 NTU.
(iii) The number of samples during the month that had equal to or less than 20/100 ml fecal coliforms and/or equal to or less than 100/100 ml total coliforms, whichever are analyzed.

(iv) The cumulative number of fecal or total coliform samples, whichever are analyzed, during the previous six months the system served water to the public.
(v) The cumulative number of samples that had equal to or less than 20/100 ml fecal coliforms or equal to or less than 100/100 ml total coliforms, whichever are analyzed, during the previous six months the system served water to the public.
(vi) The percentage of samples that had equal to or less than 20/100 ml fecal coliforms or equal to or less than 100/100 ml total coliforms , whichever are analyzed, during the previous six months the system served water to the public.
(vii) The maximum turbidity level measured during the month, the date(s) of occurrence for any measurement(s) which exceeded 5 NTU, and the date(s) the occurrence(s) was reported to the State.
(viii) For the first 12 months of recordkeeping, the dates and cumulative number of events during which the turbidity exceeded 5 NTU, and after one year of recordkeeping for turbidity measurements, the dates and cumulative number of events during which the turbidity exceeded 5 NTU in the previous 12 months the system served water to the public.
(ix) For the first 120 months of recordkeeping, the dates and cumulative number of events during which the turbidity exceeded 5 NTU, and after 10 years of recordkeeping for turbidity measurements, the dates and cumulative number of events during which the turbidity exceeded 5 NTU in the previous 120 months the system served water to the public. 

## System size by population Samples/day 1 

## ±500 1 501 to 1,000 2 1,001 to 2,500 3 2,501 to 3,300 4 

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...(2) Disinfection information specified in §141.74(b) must be reported to the State within 10 days after the end of each month the system serves water to the pub lic. Information that must be reported includes:

(i) For each day, the lowest measurement of residu al disinfectant concentration in mg/l in water entering the distribution system.
(ii) The date and duration of each period when th e residual disinfectant concentration in water entering the distribution system fell below 0.2 mg/l an d when the State was notified of the occurrence.
(iii) The daily residual disinfecta nt concentration(s) (in mg/l) and disi nfectant contact time(s) (in minutes) used for calculating the CT value(s).
(iv) If chlorine is used, the daily measurement(s) of pH of disinfected water following each point of chlorine disinfection.

(v) The daily measurement(s) of water temperature in °C following each point of disinfection.
(vi) The daily CTcalc and CTcalc/CT 99.9 values for each disinfectant measurement or sequence and the sum of all CTcalc/CT 99.9 values ((CTcalc/CT 99.9 )) before or at the first customer.

(vii) The daily determination of w hether disinfection achieves adequate Giardia cyst and virus inactivation, i.e. , whether (CTcalc/CT 99.9 ) is at least 1.0 or, where disinfectants other than chlorine are used, other indicator conditions that the State determines are appropriate, are met.
(viii) The following information on the samples ta ken in the distribution system in conjunction with total coliform monitoring pursuant to §141.72:
(A) Number of instances where the residu al disinfectant concentration is measured;
(B) Number of instances where the residual disi nfectant concentration is not me asured but heterotrophic bacteria plate count (HPC) is measured;

(C) Number of instances where the residual disinfectant concentratio n is measured but not detected and no HPC is measured;
(D) Number of instances where the residual disinfectant concentratio n is detected and where HPC is >500/ml;
(E) Number of instances where the residual di sinfectant concentration is not measured and HPC is >500/ml;
(F) For the current and previous month the system se rved water to the public, the value of “V” in the following formula:



### where:
a=the value in paragraph (a)(2)(viii)(A) of this section,
b=the value in paragraph (a)(2)(viii)(B) of this section,
c=the value in paragraph (a)(2)(viii)(C) of this section,
d=the value in paragraph (a)(2)(viii)(D) of this section, and
e=the value in paragraph (a)(2)(viii)(E) of this section.

(G) If the State determines, based on site-speci fic considerations, that a system has no means for having a sample transported and analyzed for HPC bya certified laboratory under the requisite time and temperature conditions specified by §141.74(a)(1) and that the system is providing adequate disinfection in the distribution system, the requirements of paragraph (a)(2)(viii) (A)–(F) of this section do not apply to that system.
(ix) A system need not report the data listed in paragraphs (a)(2) (i), and (iii)–(vi) of this section if all data listed in paragraphs (a)(2) (i)–(viii) of this section remain on file at the system, and the State determines that:
(A) The system has submitted to the State all the in formation required by paragraphs (a)(2) (i)–(viii) of this section for at least 12 months; and
(B) The State has determined that the system is no t required to provide filtration treatment.
(3) No later than ten days after the end of each Federal fiscal year (September 30), each system must provide to the State a report which summarizes it s compliance with all watershed control program requirements specified in §141.71(b)(2).

(4) No later than ten days after the end of each Federal fiscal year (September 30), each system must provide to the State a report on the on-site inspecti on conducted during that year pursuant to §141.71(b) (3), unless the on-site inspection was conducted by the State. If the inspection was conducted by the State, the State must provid e a copy of its report to the public water system.
(5)(i) Each system, upon discovering that a waterborne disease outbreak potentially attributable to that water system has occurred, must report that occurrenc e to the State as soon as possible, but no later than by the end of the next business day.

(ii) If at any time the turbidity exceeds 5 NTU, the sy stem must consult with the primacy agency as soon 

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...as practical, but no later than 24 hours after the exceedance is known, in accordance with the public notification requirements under §141.203(b)(3).

(iii) If at any time the residual falls below 0.2 mg/l in the water entering the distribution system, the system must notify the State as soon as possible, but no later than by the end of the next business day. The system also must notify the State by the end of the next business day whether or not the residual was restored to at least 0.2 mg/l within 4 hours.
(b) A public water system that uses a surface water source or a ground water source under the direct influence of surface water and provides filtration treatment must report monthly to the State the information specified in this paragraph (b) beginni ng June 29, 1993, or when filtration is installed, whichever is later.
(1) Turbidity measurements as required by §141.74(c)(1) must be reported within 10 days after the end of each month the system serves water to the public. Information that must be reported includes:
(i) The total number of filtered water turbi dity measurements taken during the month.
(ii) The number and percentage of filtered water turbi dity measurements taken during the month which are less than or equal to the turbidity limits specif ied in §141.73 for the filtration technology being used.

(iii) The date and value of any turbidity measuremen ts taken during the month which exceed 5 NTU.
(2) Disinfection information specified in §141.74(c) must be reported to the State within 10 days after the end of each month the system serves water to the pub lic. Information that must be reported includes:
(i) For each day, the lowest measurement of residu al disinfectant concentration in mg/l in water entering the distribution system.
(ii) The date and duration of each period when th e residual disinfectant concentration in water entering the distribution system fell below 0.2 mg/l an d when the State was notified of the occurrence.

(iii) The following information on the samples taken in the distribution system in conjunction with total coliform monitoring pursuant to §141.72:
(A) Number of instances where the residu al disinfectant concentration is measured;
(B) Number of instances where the residual disi nfectant concentration is not me asured but heterotrophic bacteria plate count (HPC) is measured;

(C) Number of instances where the residual disinfectant concentratio n is measured but not detected and no HPC is measured;
(D) Number of instances where no residual disinfectant concentration is detected and where HPC is >500/ml;
(E) Number of instances where the residual di sinfectant concentration is not measured and HPC is >500/ml;
(F) For the current and previous month the system serves water to the public, the value of “V” in the following formula:



### where:
a=the value in paragraph (b)(2)(iii)(A) of this section,
b=the value in paragraph (b)(2)(iii)(B) of this section,
c=the value in paragraph (b)(2)(iii)(C) of this section,
d=the value in paragraph (b)(2)(iii)(D) of this section, and
e=the value in paragraph (b)(2)(iii)(E) of this section.

(G) If the State determines, based on site-speci fic considerations, that a system has no means for having a sample transported and analyzed for HPC by a certified laboratory within the requisite time and temperature conditions specified by §141.74(a)(1) and that the system is providing adequate disinfection in the distribution system, the requirements of paragrap h (b)(2)(iii) (A)–(F) of this section do not apply.

(iv) A system need not report the data listed in paragraph (b)(2)(i) of this section if all data listed in paragraphs (b)(2) (i)–(iii) of this section remain on file at the system and the State determines that the system has submitted all the information required by par agraphs (b)(2) (i)–(iii) of this section for at least 12 months.
(3)(i) Each system, upon discovering that a waterborne disease outbreak potentially attributable to that water system has occurred, must report that occurrenc e to the State as soon as possible, but no later than by the end of the next business day.
(ii) If at any time the turbidity exceeds 5 NTU, the sy stem must consult with the primacy agency as soon as practical, but no later than 24 hours after the exceedance is known, in accordance with the public notification requirements under §141.203(b)(3).
(iii) If at any time the residual falls below 0.2 mg/l in the water entering the distribution system, the system must notify the State as soon as possible, but no later than by the end of the next business day. The system also must notify the State by the end of the next business day whether or not the residual was restored to at least 0.2 mg/l within 4 hours. 

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...[54 FR 27527, June 29, 1989, as amended at 65 FR 26022, May 4, 2000; 69 FR 38856, June 29, 2004]


### § 141.76 Recycle provisions.

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(a) Applicability. All subpart H systems that employ conventional filtration or direct filtration treatment and that recycle spent filter backwash water, thickener supernatant, or liquids from dewatering processes must meet the requirements in paragraphs (b) through (d) of this section.
(b) Reporting. A system must notify the State in writing by Decemeber 8, 2003, if the system recycles spent filter backwash water, thickener supernata nt, or liquids from dew atering processes. This notification must include, at a minimum, the informati on specified in paragraphs (b)(1) and (2) of this section.
(1) A plant schematic showing the origin of all flow s which are recycled (including, but not limited to, spent filter backwash water, thickener supernat ant, and liquids from dewatering processes), the hydraulic conveyance used to tr ansport them, and the location where they are re-introduced back into the treatment plant.
(2) Typical recycle flow in gallons per minute (gpm), the highest observed plant flow experienced in the previous year (gpm), des ign flow for the treatment plant (gpm), and State-approved operating capacity for the plant where the State has made such determinations.
(c) Treatment technique requirement. Any system that recycles spent filter backwash water, thickener supernatant, or liquids from dewater ing processes must return these flows through the processes of a system's existing conventional or direct filtration system as defi ned in §141.2 or at an alternate location approved by the State by June 8, 2004. If capital improvements ar e required to modify the recycle location to meet this requirement, all capital improv ements must be completed no later than June 8, 2006.
(d) Recordkeeping. The system must collect and retain on file recycle flow information specified in paragraphs (d)(1) through (6) of this section for re view and evaluation by the State beginning June 8, 2004.
(1) Copy of the recycle notification and informat ion submitted to the State under paragraph (b) of this section.
(2) List of all recycle flows and the frequency with which they are returned.
(3) Average and maximum backwash flow rate through the filters and the average and maximum duration of the filter backwash process in minutes.
(4) Typical filter run length and a written su mmary of how filter run length is determined.

(5) The type of treatment provided for the recycle flow.
(6) Data on the physical dimensions of the equaliz ation and/or treatment units, typical and maximum hydraulic loading rates, type of treatment chemicals used and average dose and frequency of use, and frequency at which solids are removed, if applicable.

[66 FR 31103, June 8, 2001]


### Subpart I—Control of Lead and Copper

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### Source: 56 FR 26548, June 7, 1991, unless otherwise noted.
§ 141.80 General requirements.

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(a) Applicability and effective dates. (1) The requirements of this subpart I constitute the national primary drinking water regulations for lead and copper. Unle ss otherwise indicated, each of the provisions of this subpart applies to community water systems an d non-transient, non-community water systems (hereinafter referred to as “water systems” or “systems”).

(2) [Reserved]
(b) Scope. These regulations establish a treatment techni que that includes requirements for corrosion control treatment, source water treatment, lead servic e line replacement, and public education. These requirements are triggered, in some cases, by lead and copper action levels measured in samples collected at consumers' taps.
(c) Lead and copper action levels. (1) The lead action level is exceeded if the concentration of lead in more than 10 percent of tap water samples collected during any monitoring period conducted in accordance with §141.86 is greater than 0.015 mg/L ( i.e. , if the “90th percentile” lead level is greater than 0.015 mg/L).
(2) The copper action level is exceeded if the conc entration of copper in more than 10 percent of tap water samples collected during any monitoring period conducted in accordance with §141.86 is greater than 1.3 mg/L ( i.e. , if the “90th percentile” copper level is greater than 1.3 mg/L).
(3) The 90th percentile lead and copper levels shall be computed as follows:

(i) The results of all lead or copper samples taken during a monitoring period shall be placed in ascending order from the sample with the lowest concentration to the sample with the highest concentration. Each sampling result shall be assigned a number, ascending by si ngle integers beginning 

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...with the number 1 for the sample with the lowest contaminant level. The number assigned to the sample with the highest contaminant level shall be equal to the total number of samples taken.

(ii) The number of samples taken during the m onitoring period shall be multiplied by 0.9.
(iii) The contaminant conc entration in the numbered sample yielded by the calculation in paragraph (c) (3)(ii) is the 90th percentile contaminant level.
(iv) For water systems serving fewer than 100 people that collect 5 samples per monitoring period, the 90th percentile is computed by taking the average of the highest and second highest concentrations.

(v) For a public water system that has been allowed by the State to collect fewer than five samples in accordance with §141.86(c), the sample result with the highest concentration is considered the 90th percentile value.
(d) Corrosion control treatment requirements. (1) All water systems shall install and operate optimal corrosion control treatment as defined in §141.2.
(2) Any water system that complies with the applic able corrosion control treatment requirements specified by the State under §§141.81 and 141.82 shall be deemed in compliance with the treatment requirement contained in paragraph (d)(1) of this section.
(e) Source water treatment requirements. Any system exceeding the lead or copper action level shall implement all applicable source water treatment requirements specified by the State under §141.83.
(f) Lead service line replacement requirements. Any system exceeding the lead action level after implementation of applicable corrosion control and s ource water treatment requirements shall complete the lead service line replacement re quirements contained in §141.84.

(g) Public education requirements. Pursuant to §141.85, all water systems must provide a consumer notice of lead tap water monitoring results to perso ns served at the sites (taps ) that are tested. Any system exceeding the lead action level shal l implement the public education requirements.
(h) Monitoring and analytical requirements. Tap water monitoring for lead and copper, monitoring for water quality parameters, source water monitorin g for lead and copper, and analyses of the monitoring results under this subpart shall be completed in compliance with §§141.86, 141.87, 141.88, and 141.89.
(i) Reporting requirements. Systems shall report to the State any i nformation required by the treatment provisions of this subpart and §141.90.
(j) Recordkeeping requirements. Systems shall maintain records in accordance with §141.91.
(k) Violation of national primary drinking water regulations. Failure to comply with the applicable requirements of §§141.80–141.91, including requirements established by the State pursuant to these provisions, shall constitute a violation of the national primary drinking water regulations for lead and/or copper.
[56 FR 26548, June 7, 1991; 57 FR 28788, June 29, 1992, as amended at 72 FR 57814, Oct. 10, 2007]


### § 141.81 Applicability of corrosion control treatment steps to small, medium-size and large water systems.

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(a) Systems shall complete the applicable corros ion control treatment requirements described in §141.82 by the deadlines established in this section.
(1) A large system (serving >50,000 persons) sha ll complete the corrosion control treatment steps specified in paragraph (d) of this section, unless itis deemed to have optimized corrosion control under paragraph (b)(2) or (b)(3) of this section.
(2) A small system (serving ≤ 3300 persons) and a medium-size system (serving >3,300 and ≤ 50,000 persons) shall complete the corrosio n control treatment steps specified in paragraph (e) of this section, unless it is deemed to have optimized corrosion control under paragraph (b)(1), (b)(2), or (b)(3) of this section.
(b) A system is deemed to have optimized corros ion control and is not required to complete the applicable corrosion control treatm ent steps identified in this section if the system satisfies one of the criteria specified in paragraphs (b)(1) through (b)(3) of this section. Any such system deemed to have optimized corrosion control under this paragraph, and which has treatme nt in place, shall continue to operate and maintain optimal corros ion control treatment and meet any requirements that the State determines appropriate to ensure optimal co rrosion control treatment is maintained.
(1) A small or medium-size water system is deemed to have optimized corrosion control if the system meets the lead and copper action le vels during each of two consecuti ve six-month monitoring periods conducted in accordance with §141.86.
(2) Any water system may be deemed by the State to have optimized corrosion control treatment if the system demonstrates to the satisfacti on of the State that it has conducte d activities equivalent to the corrosion control steps applicable to such system under this section. If the State makes this determination, it shall provide the sys tem with written notice explaini ng the basis for its decision and shall specify the water quality control parameters representing optimal corrosion control in accordance with §141.82(f). Water systems deemed to have optimi zed corrosion control under this paragraph shall operate in compliance with the State-designated optimal water quality control parameters in accordance with §141.82(g) and continue to conduct lead and copper tap and water quality parameter sampling in accordance with §141.86(d)(3) and §141.87(d), respec tively. A system shall provide the State with the following information in order to support a determination under this paragraph:
(i) The results of all test samples collected for eac h of the water quality parameters in §141.82(c)(3).
(ii) A report explaining the test methods used by the water system to evaluate the corrosion control treatments listed in §141.82(c)(1), the results of all tests conducted, and the basis for the system's 

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...selection of optimal corrosion control treatment;
(iii) A report explaining how corrosion control has been installed and how it is being maintained to insure minimal lead and copper concentrations at consumers' taps; and
(iv) The results of tap water samples collected in accordance with §141.86 at least once every six months for one year after corrosio n control has been installed.
(3) Any water system is deemed to have optimized corrosion control if it submits results of tap water monitoring conducted in accordance with §141.8 6 and source water monitoring conducted in accordance with §141.88 that demonstrates for two consecutive 6-month monitoring periods that the difference between the 90th percentile tap water lead level computed under §141.80(c)(3), and the highest source water lead concentr ation is less than the Practical Quanti tation Level for lead specified in §141.89(a)(1)(ii).
(i) Those systems whose hig hest source water lead level is below the Method Detection Limit may also be deemed to have optimized corrosion control under thi s paragraph if the 90th percentile tap water lead level is less than or equal to the Practical Qua ntitation Level for lead for two consecutive 6-month monitoring periods.
(ii) Any water system deemed to have optimized corrosion control in accordance with this paragraph shall continue monitoring for lead and copper at the tap no less frequently than once every three calendar years using the reduced number of sites s pecified in §141.86(c) and collecting the samples at times and locations specified in §141.86(d)(4)(iv). Any such system that has not conducted a round of monitoring pursuant to §141.86(d) since September 30 , 1997, shall complete a round of monitoring pursuant to this paragraph no later than September 30, 2000.
(iii) Any water system deemed to have optimized corros ion control pursuant to this paragraph shall notify the State in writing pursuant to §141.90(a)(3) of any upcoming long-term change in treatment or addition of a new source as described in that section. The State must review and approve the addition of a new source or long-term change in water treatment before it is implemented by the water system. The State may require any such system to conduct additional monitoring or to take other action the State deems appropriate to ensure that such systems maintain mini mal levels of corrosion in the distribution system.
(iv) As of July 12, 2001, a system is not deem ed to have optimized corrosion control under this paragraph, and shall implement corrosion control treatment pursuant to paragraph (b)(3)(v) of this section unless it meets the copper action level.
(v) Any system triggered into corrosion control because it is no longer deemed to have optimized corrosion control under this paragraph shall implementcorrosion control treatment in accordance with the deadlines in paragraph (e) of this section. An y such large system shall adhere to the schedule specified in that paragraph for medium-size systems, with the time periods for completing each step being triggered by the date the system is no longer deemed to have optimized corrosion control under this paragraph.
(c) Any small or medium-size water system that is required to complete the corrosion control steps due to its exceedance of the lead or copper action leve l may cease completing the treatment steps whenever the system meets both action levels during each of two consecutive moni toring periods conducted pursuant to §141.86 and submits the results to the State. If any such water system thereafter exceeds the lead or copper action level during any monitor ing period, the system (or the State, as the case may be) shall recommence completion of the applicable treatment steps, beginning with the first treatment step which was not previously completed in its enti rety. The State may require a system to repeat treatment steps previously completed by the system wh ere the State determines that this is necessary to implement properly the treatment requirements of this se ction. The State shall notify the system in writing of such a determination and explain the basis for its decision. The requirement for any small- or medium-size system to implement corrosion control tr eatment steps in accordance with paragraph (e) of this section (including systems deemed to have opti mized corrosion control un der paragraph (b)(1) of this section) is triggered whenever any small- or m edium-size system exceeds th e lead or copper action level.
(d) Treatment steps and deadlines for large systems. Except as provided in paragraph (b) (2) and (3) of this section, large systems shall complete the following corrosion control treatment steps (described in the referenced portions of §§141.82, 141.8 6, and 141.87) by the indicated dates.
(1) Step 1: The system shall conduct initial monitoring (§141.86(d)(1) and §141.87(b)) during two consecutive six-month monitoring periods by January 1, 1993.
(2) Step 2: The system shall complete corrosion control studies (§141.82(c)) by July 1, 1994.
(3) Step 3: The State shall designate optimal corrosion control treatment (§141.82(d)) by January 1, 1995.
(4) Step 4: The system shall install optimal corrosion c ontrol treatment (§141.82(e)) by January 1, 1997.
(5) Step 5: The system shall complete follow-up samplin g (§141.86(d)(2) and §141.87(c)) by January 1, 1998.
(6) Step 6: The State shall review installation of treatme nt and designate optimal water quality control parameters (§141.82(f)) by July 1, 1998.
(7) Step 7: The system shall operate in compliance with the State-specified optimal water quality control parameters (§141.82(g)) and continue to conduct tap sampling (§141.86(d)(3) and §141.87(d)).

(e) Treatment Steps and deadlines for small and medium-size systems. Except as provided in paragraph (b) of this section, small and medium-size systems shall complete the following corrosion control treatment steps (described in the referenced portions of §§141.82, 141.86 and 141.87) by the indicated time periods.
(1) Step 1: The system shall conduct initial tap sampling (§141.86(d)(1) and §141.87(b)) until the system either exceeds the lead or copper action level or becomes eligible for reduced monitoring under §141.86 (d)(4). A system exceeding the lead or copper action level shall recommend optimal corrosion control treatment (§141.82(a)) within six months after the end of the monitoring period during which it exceeds one of the action levels.
(2) Step 2: Within 12 months after the end of the monitoring period during which a system exceeds the 

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...lead or copper action level, the State may requir e the system to perform co rrosion control studies (§141.82(b)). If the State does not require the system to perform such studies, the State shall specify optimal corrosion control treatment (§1 41.82(d)) within the following timeframes:

(i) For medium-size systems, withi n 18 months after the end of the monitoring period during which such system exceeds the lead or copper action level.
(ii) For small systems, within 24 months after the end of the monitoring period during which such system exceeds the lead or copper action level.
(3) Step 3: If the State requires a system to perform corrosio n control studies under step 2, the system shall complete the studies (§141.82(c)) within 18 months after the State requires that such studies be conducted.
(4) Step 4: If the system has performed corrosion control st udies under step 2, the State shall designate optimal corrosion control treatment (§141.82(d)) within 6 months after completion of step 3.

(5) Step 5: The system shall install optimal corrosion control treatment (§141.82(e)) within 24 months after the State designates such treatment.
(6) Step 6: The system shall complete follow-up sampling (§141.86(d)(2) and §141.87(c)) within 36 months after the State designates opti mal corrosion control treatment.
(7) Step 7: The State shall review the system's installation of treatment and designate optimal water quality control parameters (§141.82(f)) within 6 months after completion of step 6.
(8) Step 8: The system shall operate in compliance with the State-designated optimal water quality control parameters (§141.82(g)) and continue to conduct tap sampling (§141.86(d)(3) and §141.87(d)).

[56 FR 26548, June 7, 1991, as amended at 59 FR 33862, June 30, 1994; 65 FR 2004, Jan. 12, 2000; 72 FR 57814, Oct. 10, 2007]


### § 141.82 Description of corrosion control treatment requirements.

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Each system shall complete the corrosion control treatment requirements described below which are applicable to such system under §141.81.
(a) System recommendation regarding corrosion control treatment. Based upon the results of lead and copper tap monitoring and water quali ty parameter monitoring, small and medium-size water systems exceeding the lead or copper action level shall recomm end installation of one or more of the corrosion control treatments listed in paragraph (c)(1) of this section which the system believes constitutes optimal corrosion control for that system. The State may require the system to conduct additional water quality parameter monitoring in accordance with §141.87(b) to assist the State in reviewing the system's recommendation.
(b) State decision to require studies of corrosion control treatment (applicable to small and medium-size systems). The State may require any small or medium-size system that exceeds the lead or copper action level to perform corrosion control studies unde r paragraph (c) of this section to identify optimal corrosion control treatment for the system.
(c) Performance of corrosion control studies. (1) Any public water system performing corrosion control studies shall evaluate the effectiveness of each of the following treatments, and, if appropriate, combinations of the following treatments to identifythe optimal corrosion control treatment for that system:
(i) Alkalinity and pH adjustment;
(ii) Calcium hardness adjustment; and

(iii) The addition of a phosphate or silicate based corrosion inhibitor at a co ncentration sufficient to maintain an effective residual concentration in all test tap samples.
(2) The water system shall evaluate eac h of the corrosion control treatm ents using either pipe rig/loop tests, metal coupon tests, partial-s ystem tests, or analyses based on documented analogous treatments with other systems of similar size, water chemis try and distribution system configuration.
(3) The water system shall measure the following waterquality parameters in anytests conducted under this paragraph before and after evaluating the corrosion control treatments listed above:
(i) Lead;

(ii) Copper;
(iii) pH;
(iv) Alkalinity;

(v) Calcium;
(vi) Conductivity;
(vii) Orthophosphate (when an i nhibitor containing a phosph ate compound is used);

(viii) Silicate (when an inhibitor con taining a silicate compound is used);
(ix) Water temperature.
(4) The water system shall identify all chemical or phys ical constraints that limit or prohibit the use of a 

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...particular corrosion control treatment and document su ch constraints with at le ast one of the following:
(i) Data and documentation showing t hat a particular corrosion control treatment has adversely affected other water treatment processes when used by another water system with comparable water quality characteristics; and/or
(ii) Data and documentation demonstrating that the w ater system has previously attempted to evaluate a particular corrosion control treatment and has found that the treatment is ineffecti ve or adversely affects other water quality treatment processes.
(5) The water system shall evaluate th e effect of the chemicals used for corrosion control treatment on other water quality treatment processes.
(6) On the basis of an analysis of the data genera ted during each evaluation, the water system shall recommend to the State in writing the treatment option that the corrosion control studies indicate constitutes optimal corrosion control treatment for that system. The water sy stem shall provide a rationale for its recommendation along with all supporting documentation specified in paragraphs (c) (1) through (5) of this section.
(d) State designation of optimal corr osion control treatment. (1) Based upon consideration of available information including, where applicable, studies performed under paragraph (c) of this section and a system's recommended treatment alternative, the S tate shall either approve the corrosion control treatment option recommended by the system, or designate alternative corrosion control treatment(s) from among those listed in paragraph (c)(1) of this section. When designating optimal treatment the State shall consider the effects that additional corr osion control treatment will have on water quality parameters and on other water quality treatment processes.
(2) The State shall notify the system of its decision on optimal corrosion control treatment in writing and explain the basis for this determination. If the State requests additional information to aid its review, the water system shall provide the information.
(e) Installation of optimal corrosion control. Each system shall properly install and operate throughout its distribution system the optimal corrosion control tr eatment designated by the State under paragraph (d) of this section.

(f) State review of treatment and specification of optimal water quality control parameters. The State shall evaluate the results of all lead and copper tap samples and water quality parameter samples submitted by the water system and determine whe ther the system has properly installed and operated the optimal corrosion control treatment designated by the State in paragraph (d) of this section. Upon reviewing the results of tap water and water quality parameter monitoring by the system, both before and after the system installs optimal corrosion control treatment, the St ate shall designate:
(1) A minimum value or a range of values for pH me asured at each entry point to the distribution system;
(2) A minimum pH value, measured in all tap sample s. Such value shall be equal to or greater than 7.0, unless the State determines that meeting a pH leve l of 7.0 is not technologically feasible or is not necessary for the system to optimize corrosion control;
(3) If a corrosion inhibitor is use d, a minimum concentration or a range of concentrations for the inhibitor, measured at each entry point to the distribution system and in all tap samples, that the State determines is necessary to form a passivating film on the inter ior walls of the pipes of the distribution system;
(4) If alkalinity is adjusted as pa rt of optimal corrosion control treatment, a minimum concentration or a range of concentrations for alkalinity, measured at each entry point to the distribution system and in all tap samples;
(5) If calcium carbonate stabilization is used as part of corrosion control, a minimum concentration or a range of concentrations for calcium, measured in all tap samples.

The values for the applicable water quality control parameters listed above shall be those that the State determines to reflect optimal corros ion control treatment for the system. The State may designate values for additional water quality control parameters determined by the State to reflect optimal corrosion control for the system. The State shall notify the system in writing of these determinations and explain the basis for its decisions.

(g) Continued operation and monitoring. All systems optimizing corrosion control shall continue to operate and maintain optimal corrosi on control treatment, including maintaining water quality parameters at or above minimum values or withi n ranges designated by the State under paragraph (f) of this section, in accordance with this paragraph for all samples co llected under §141.87(d) through (f). Compliance with the requirements of this paragraph shall be determined every six months, as specified under §141.87(d). A water system is out of compliance with the requirements of this paragraph for a six-month period if it has excursions for any State-specified parameter on more than nine days during the period. A n excursion occurs whenever the daily value for one or more of the water quality parameters measured at a sampling location is below the minimum val ue or outside the range designated by the State. Daily values are calculated as follows. States have discretion to delete results of obvious sampling errors from this calculation.
(1) On days when more than one measurement for the water quality parameter is collected at the sampling location, the daily value shall be the average of all results collected during the day regardless of whether they are collected through continuous monitorin g, grab sampling, or a combination of both. If EPA has approved an alternative formula under §142.16 of this chapter in the State's application for a program revision submitted pursuant to §142.12 of this chapter, the State's formula shall be used to aggregate multiple measurements taken at a sampling point for the water quality parameter in lieu of the formula in this paragraph.
(2) On days when only one measurement for the water quality parameter is collected at the sampling location, the daily value shall be the result of that measurement.
(3) On days when no measurement is collected for the water quality parameter at the sampling location, the daily value shall be the daily value calculated on the most recent day on which the water quality parameter was measured at the sample site.
(h) Modification of State treatment decisions. Upon its own initiative or in response to a request by a water system or other interested party, a State may modify its determination of the optimal corrosion control treatment under paragraph (d) of this section or optimal water quality control parameters under 

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...paragraph (f) of this section. A reques t for modification by a s ystem or other interested party shall be in writing, explain why the modification is appropri ate, and provide supporting documentation. The State may modify its determination where itconcludes that such change is necessary to ensure that the system continues to optimize corrosion control treatment. A revised determination shall be made in writing, set forth the new treatment requirements, expl ain the basis for the State's decision, and provide an implementation schedule for compl eting the treatmen t modifications.
(i) Treatment decisions by EPA in lieu of the State. Pursuant to the procedures in §142.19, the EPA Regional Administrator may review treatment determinations made by a State under paragraphs (d), (f), or (h) of this section and issue federal treatment determinations consistent with the requirements of those paragraphs where the Regional Administrator finds that:

(1) A State has failed to issue a treatment deter mination by the applicable deadlines contained in §141.81,

(2) A State has abused its discretion in a substantial number of cases or in cases affecting a substantial population, or
(3) The technical aspects of a S tate's determination would be indefens ible in an expected Federal enforcement action taken against a system.

[56 FR 26548, June 7, 1991, as amended at 65 FR 2004, Jan. 12, 2000]


### § 141.83 Source water treatment requirements.

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Systems shall complete the applicable source watermonitoring and treatment requirements (described in the referenced portions of paragraph (b) of this section, and in §§141.86, and 141.88) by the following deadlines.
(a) Deadlines for completing source water treatment steps— (1) Step 1: A system exceeding the lead or copper action level shall complete lead and copper source water monitoring (§141.88(b)) and make a treatment recommendation to the State (§141.83(b)(1)) no later than 180 days after the end of the monitoring period during which the lead or copper action level was exceeded.
(2) Step 2: The State shall make a determination regarding source water treatment (§141.83(b)(2)) within 6 months after submission of monitoring results under step 1.
(3) Step 3: If the State requires installation of source w ater treatment, the system shall install the treatment (§141.83(b)(3)) within 24 months after completion of step 2.
(4) Step 4: The system shall complete follow-up tap water monitoring (§141.86(d)(2) and source water monitoring (§141.88(c)) within 36 months after completion of step 2.

(5) Step 5: The State shall review the system's installation and operation of source water treatment and specify maximum permissible source water levels (§ 141.83(b)(4)) within 6 months after completion of step 4.
(6) Step 6: The system shall operate in compliance with the State-specified maximum permissible lead and copper source water levels (§141.83(b)(4)) and continue source water monitoring (§141.88(d)).
(b) Description of source water treatment requirements —(1) System treatment recommendation. Any system which exceeds the lead or copper action level shall recommend in writing to the State the installation and operation of one of the source water treatments listed in paragraph (b)(2) of this section. Asystem may recommend that no treatment be installed based upon a demonstration that source water treatment is not necessary to minimize lead and copper levels at users' taps.
(2) State determination regarding source water treatment. The State shall complete an evaluation of the results of all source water samples submitted by the water system to determine whether source water treatment is necessary to minimize lead or copper levels in water delivered to users' taps. If the State determines that treatment is needed, the State shall ei ther require installation and operation of the source water treatment recommended by the system (i f any) or require the installation and operation of another source water treatment from among the following: Ion exchange, reverse osmosis, lime softening or coagulation/filtration. If the State requests additional information to aid in its review, the water system shall provide the infor mation by the date specified by the State in its request. The State shall notify the system in writing of its determ ination and set forth the basis for its decision.

(3) Installation of source water treatment. Each system shall properly install and operate the source water treatment designated by the State under paragraph (b)(2) of this section.
(4) State review of source water treatment and specification of maximum permissible source water levels. The State shall review the source water samples taken by the water system both before and after the system installs source water treatment, and determi ne whether the system has properly installed and operated the source water treatment designated by the State. Based upon its review, the State shall designate the maximum permissible lead and copper concentrations for fini shed water entering the distribution system. Such levels shall reflect the contaminant removal capability of the treatment properly operated and maintained. The State shall notify the s ystem in writing and explain the basis for its decision.
(5) Continued operation and maintenance. Each water system shall maintain lead and copper levels below the maximum permissible concentrations des ignated by the State at each sampling point monitored in accordance with §141.88 . The system is out of compliance with this paragraph if the level of lead or copper at any sampling point is greater than the maximum permissible concentration designated by the State.

(6) Modification of State treatment decisions. Upon its own initiative or in response to a request by a water system or other interested party, a State may modify its determination of the source water treatment under paragraph (b)(2) of this section, or maximum permissible lead and copper concentrations for finished water entering the distribu tion system under paragraph (b)(4) of this section. Arequest for modification bya system or other interested party shall be in writing, explain why the modification is appropriate, and provide sup porting documentation. The State may modify its determination where it concludes that such change is necessary to ensure that the system continues to minimize lead and copper concentrations in source water. A revised determination shall be made in 

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...writing, set forth the new treatment requirements, expl ain the basis for the State's decision, and provide an implementation schedule for compl eting the treatmen t modifications.

(7) Treatment decisions by EPA in lieu of the State. Pursuant to the procedures in §142.19, the EPA Regional Administrator may review treatment determinations made by a State under paragraphs (b) (2), (4), or (6) of this section and issue Federal treatm ent determinations consistent with the requirements of those paragraphs where the Administrator finds that:
(i) A State has failed to issue a treatment determi nation by the applicable deadlines contained in §141.83(a),
(ii) A state has abused its discretion in a substantial number of cases or in cases affecting a substantial population, or
(iii) The technical aspects of a State's determinati on would be indefensible in an expected Federal enforcement action taken against a system.

[56 FR 26548, June 7, 1991, as amended at 72 FR 57815, Oct. 10, 2007]


### § 141.84 Lead service line replacement requirements.

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(a) Systems that fail to meet the lead action level in tap samples taken pursuant to §141.86(d)(2), after installing corrosion control and/or source water treatment (whichever sampling occurs later), shall replace lead service lines in accordance with the requ irements of this section. If a system is in violation of §141.81 or §141.83 for failure to install source w ater or corrosion control treatment, the State may require the system to commence lead service line repl acement under this section after the date by which the system was required to conduct monitoring under §141.86(d)(2) has passed.

(b)(1) A water system shall replace annually at least 7 percent of the initial number of lead service lines in its distribution system. The initial number of lead se rvice lines is the number of lead lines in place at the time the replacement program begins. The system shall identify the in itial number of lead service lines in its distribution system, including an identifica tion of the portion(s) owned by the system, based on a materials evaluation, incl uding the evaluation required under §141.86(a) and relevant legal authorities (e.g., contracts, local ordinances) regardin g the portion owned by the system. The first year of lead service line replacement shall begin on the fi rst day following the end of the monitoring period in which the action level was exceeded under paragraph (a) of this section. If monitoring is required annually or less frequently, the end of the monitoring period is September 30 of the calendar year in which the sampling occurs. If the State has establi shed an alternate monitoring period, then the end of the monitoring period will be the last day of that period.
(2) Any water system resuming a lead service line re placement program after the cessation of its lead service line replacement program as allowed by parag raph (f) of this section shall update its inventory of lead service lines to include those sites that were previously determined not to require replacement through the sampling provision under paragraph (c) of this section. The system will then divide the updated number of remaining lead service lines by the number of remaining years in the program to determine the number of lines that must be replaced pe r year (7 percent lead service line replacement is based on a 15-year replacement program, so, fo r example, systems resuming lead service line replacement after previously conduc ting two years of replacement woul d divide the updated inventory by 13). For those systems that have completed a 15-year lead service line replacement program, the State will determine a schedule for replacing or retest ing lines that were previously tested out under the replacement program when the system re-exceeds the action level.
(c) A system is not required to replac e an individual lead service line if the lead concentration in all service line samples from that line, taken pursuant to §141.86(b)(3), is less than or equal to 0.015 mg/L.
(d) A water system shall replace that portion of the lead service line that it owns. In cases where the system does not own the entire lead service line, the system shall notify the owner of the line, or the owner's authorized agent, that the system will replace the portion of the service line that it owns and shall offer to replace the owner's portion of the line. A system is not required to bear the cost of replacing the privately-owned portion of the line, nor is it required to replace the privately-owned portion where the owner chooses not to pay the cost of replacing the privately-owned portion of the line, or where replacing the privately-owned portion would be prec luded by State, local or common law. A water system that does not replace the entire length of the service line also shall complete the following tasks.
(1) At least 45 days prior to commencing with the pa rtial replacement of a lead service line, the water system shall provide notice to the resident(s) of all buildings served by the li ne explaining that they may experience a temporary increase of lead levels in thei r drinking water, along with guidance on measures consumers can take to minimize their exposure to lead. The State may allow the water system to provide notice under the previous sentence less than 45 days prior to commencing partial lead service line replacement where such replacement is in co njunction with emergency repairs. In addition, the water system shall inform the resident(s) served bythe line that the system will, at the system's expense, collect a sample from each partially-replac ed lead service line that is representative of the water in the service line for analysis of lead content, as prescribed under §141.86(b)(3), within 72 hours after the completion of the partial replacement of the service line. The system shall collect the sample and report the results of the analysis to the owner and the resident(s) served by the line within three business days of receiving the results. Mailed notices post-marked within three business days of receiving the results shall be considered “on time.”
(2) The water system shall provide the information required by paragraph (d)(1) of this section to the residents of individual dwellings by mail or by oth er methods approved by the State. In instances where multi-family dwellings are served by the line, the water system shall have the option to post the information at a conspicuous location.

(e) The State shall require a system to replace lead service lines on a shorter schedule than that required by this section, taking into account the number of lead service lines in the system, where such a shorter replacement schedule is feasible. The State sh all make this determination in writing and notify the system of its finding within 6 months after the syst em is triggered into lead service line replacement based on monitoring referenced in paragraph (a) of this section.

(f) Any system may cease replacing lead service lines whenever first draw samples collected pursuant to §141.86(b)(2) meet the lead action level during each of two consecutive moni toring periods and the system submits the results to the State. If first draw tap samples collected in any such system thereafter exceeds the lead action level, the system shall reco mmence replacing lead service lines pursuant to paragraph (b)(2) of this section. 

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...(g) To demonstrate compliance with paragraphs (a) through (d) of this section, a system shall report to the State the information specified in §141.90(e).

[56 FR 26548, June 7, 1991; 57 FR 28788, June 29, 1992, as amended at 65 FR 2005, Jan. 12, 2000; 72 FR 57815, Oct. 10, 2007]


### § 141.85 Public education and supplemental monitoring requirements.

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A ll water systems must deliver a consumer notice of lead tap water monitoring results to persons served by the water system at sites that are tested, as specif ied in paragraph (d) of this section. A water system that exceeds the lead action level based on tap water samples collected in accordance with §141.86 shall deliver the public education materials contained in paragraph (a) of this section in accordance with the requirements in paragraph (b) of this section. Water systems that exceed the lead action level must sample the tap water of any customer who requests it in accordance with paragraph (c) of this section.
(a) Content of written public education materials —(1) Community water systems and non-transient noncommunity water systems. Water systems must include the following elements in printed materials (e.g., brochures and pamphlets) in the same order as listed below. In addition, language in paragraphs (a)(1) (i) through (ii) and (a)(1)(vi) of this section must be included in the materials, exactly as written, except for the text in brackets in thes e paragraphs for which the water system must include system-specific information. Any additional information presented by a water system must be consistent with the information below and be in plain language that can be understood by the general public. Water systems must submit all written public education materials to the State prior to delivery. The State may require the system to obtain approval of the content of written public materials prior to delivery.
(i) IMPORTANT INFORMATION ABOUT LEAD IN YOUR DRINKING WATER. [INSERT NAME OF WATER SYSTEM] found elevated levels of lead in drin king water in some homes/buildings. Lead can cause serious health problems, especially for pr egnant women and young children. Please read this information closely to see what you can do to reduce lead in your drinking water.

(ii) Health effects of lead. Lead can cause serious health problems if too much enters your body from drinking water or other sources. It can cause damage to the brain and kidneys, and can interfere with the production of red blood cells that carry oxygen to all parts of your body. The greatest risk of lead exposure is to infants, young children, and pregnant women. Scientists have linked the effects of lead on the brain with lowered IQ in children. Adults with kidney problems and high blood pressure can be affected by low levels of lead more than healthy a dults. Lead is stored in the bones, and it can be released later in life. During pregnancy, the child re ceives lead from the mother's bones, which may affect brain development.

(iii) Sources of lead. (A) Explain what lead is.
(B) Explain possible sources of lead in drinking water and how lead enters drinking water. Include information on home/building plumbing materials and service lines that may contain lead.
(C) Discuss other important sources of lead exposu re in addition to drinking water (e.g., paint).
(iv) Discuss the steps the cons umer can take to reduce their expos ure to lead in drinking water.
(A) Encourage running the water to flush out the lead.
(B) Explain concerns with using hot water from the tap and specifically caution against the use of hot water for preparing baby formula.
(C) Explain that boiling water does not reduce lead levels.

(D) Discuss other options consumers can take to reduce exposure to lead in drinking water, such as alternative sources or treatment of water.
(E) Suggest that parents have their child's blood tested for lead.
(v) Explain why there are el evated levels of lead in the system's drinking water (if known) and what the water system is doing to reduce the lead levels in homes/buildings in this area.
(vi) For more information, call us at [INSERT YO UR NUMBER] [(IF APPLICABLE) , or visit our Web site at [INSERT YOUR WEB SITE HERE]]. For more i nformation on reducing lead exposure around your home/building and the health effects of lead, visit EPA's Web site at http://www.epa.gov/lead or contact your health care provider.
(2) Community water systems. In addition to including the elements specified in paragraph (a)(1) of this section, community water systems must:
(i) Tell consumers how to get their water tested.
(ii) Discuss lead in plumbing components and the difference between low lead and lead free.
(b) Delivery of public education materials. (1) For public water systems serving a large proportion of nonEnglish speaking consumers, as determined by the State, the public education materials must contain information in the appropriate language(s) regarding the importance of the notice or contain a telephone number or address where persons served may contact the water system to obtain a translated copy of the public education materials or to requ est assistance in the appropriate language.
(2) A community water system that exceeds the lead action level on the basis of tap water samples collected in accordance with §141.86, and that is not already conducting publiceducation tasks under this section, must conduct the public education tasks under this section within 60 days after the end of the monitoring period in which the exceedance occurred:
(i) Deliver printed materi als meeting the content re quirements of paragraph (a) of this section to all bill paying customers.
(ii)(A) Contact customers who are most at risk by delivering education materials that meet the content 

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...requirements of paragraph (a) of this section to local public health agencies even if they are not located within the water system's service area, along with an informational notice that enco urages distribution to all the organization's potentially affected customers or community water system's users. The water system must contact the local public health agencies directly by phone or in person. The local public health agencies may provide a specific list of addit ional community based organizations serving target populations, which may include organizations outside the service area of the water system. If such lists are provided, systems must deliver education mate rials that meet the content requirements of paragraph (a) of this section to all organizations on the provided lists.
(B) Contact customers who are most at risk by de livering materials that meet the content requirements of paragraph (a) of this section to the following organi zations listed in 1 through 6 that are located within the water system's service area, along with an inform ational notice that encourage s distribution to all the organization's potentially affected custom ers or community water system's users:
( 1 ) Public and private schools or school boards.

( 2 ) Women, Infants and Children (WIC) and Head Start programs.
( 3 ) Public and private hospitals and medical clinics.
( 4 ) Pediatricians.

( 5 ) Family planning clinics.
( 6 ) Local welfare agencies.
(C) Make a good faith effort to locate the following organizations within the service area and deliver materials that meet the content requirements of pa ragraph (a) of this section to them, along with an informational notice that encourages distribution to al l potentially affected customers or users. The good faith effort to contact at-risk customers may include requesting a specific contact list of these organizations from the local public health agencies, even if the agencies are not located within the water system's service area:
( 1 ) Licensed childcare centers

( 2 ) Public and private preschools.
( 3 ) Obstetricians-Gynecol ogists and Midwives.
(iii) No less often than quarterly, provide information on or in each water bill as long as the system exceeds the action level for lead. The message on the water bill must include the following statement exactly as written except for the text in brackets for which the water system must include system-specific information: [INSERT NAME OF WATER SYSTEM] found high levels of lead in drinking water in some homes. Lead can cause serious health problems. For more information please call [INSERT NAME OF WATER SYSTEM] [or visit (INSERT YOUR WEB SITE HERE)]. The message or delivery mechanism can be modified in consultation with the State; s pecifically, the State may allow a separate mailing of public education materials to customers if the water system cannot place the information on water bills.
(iv) Post material meeting the content requirements of paragraph (a) of this section on the water system's Web site if the system se rves a population greater than 100,000.
(v) Submit a press release to newsp aper, television and radio stations.
(vi) In addition to paragraphs (b)(2)(i) through (v) of this section, systems must implement at least three activities from one or more categories listed bel ow. The educational content and selection of these activities must be determined in consultation with the State.

(A) Public Service Announcements.
(B) Paid advertisements.
(C) Public Area Information Displays.

(D) E-mails to customers.
(E) Public Meetings.
(F) Household Deliveries.

(G) Targeted Individual Customer Contact.
(H) Direct material distribution to all multi-family homes and institutions.
(I) Other methods approved by the State.

(vii) For systems that are required to conduct monitoring annually or less frequently, the end of the monitoring period is September 30 of the calendar year in which the sampling occurs, or, if the State has established an alternate monitoring period, the last day of that period.

(3) As long as a community water sys tem exceeds the action level, it must repeat the activities pursuant to paragraph (b)(2) of this section as described in paragraphs (b)(3)(i) through (iv) of this section.
(i) A community water system shall repeat the tasks contai ned in paragraphs (b)(2)(i), (ii) and (vi) of this section every 12 months.
(ii) A community water system shall repeat tasks contai ned in paragraph (b)(2)(iii) of this section with each billing cycle.
(iii) A community water system serving a populati on greater than 100,000 shall post and retain material on a publicly accessible Web site pursuant to paragraph (b)(2)(iv) of this section. 

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...(iv) The community water system shall repeat the tas k in paragraph (b)(2)(v) of this section twice every 12 months on a schedule agreed upon with the State. Th e State can allow activities in paragraph (b)(2) of this section to extend beyond the 60-day requiremen t if needed for implementation purposes on a case-by-case basis; however, this extension must be ap proved in writing by the State in advance of the 60-day deadline.
(4) Within 60 days after the end of the monitoring period in which the exceedance occurred (unless it already is repeating public education tasks pursuant to paragraph (b)(5) of this section), a non-transient non-community water system shall deliver the public education materials specified by paragraph (a) of this section as follows:

(i) Post informational posters on lead in drinking water in a public place or common area in each of the buildings served by the system; and
(ii) Distribute informational pamphl ets and/or brochures on lead in drinking water to each person served by the non-transient non-community water system. The State may allow the system to utilize electronic transmission in lieu of or combined with printed mater ials as long as it achieves at least the same coverage.
(iii) For systems that are required to conduct monitoring annually or less frequently, the end of the monitoring period is September 30 of the calendar year in which the sampling occurs, or, if the State has established an alternate monitoring period, the last day of that period.
(5) A non-transient non-community water system shal l repeat the tasks contained in paragraph (b)(4) of this section at least once during each calendar year in which the system exceeds the lead action level. The State can allow activities in (b )(4) of this section to extend beyond the 60-day requirement if needed for implementation purposes on a case-by-case basis; however, this extension must be approved in writing by the State in advance of the 60-day deadline.
(6) A water system may discontinue delivery of public education materials if the system has met the lead action level during the most recent six-month monitoring period conducted pursuant to §141.86. Such a system shall recommence public education in accordance with this section if it subsequently exceeds the lead action level du ring any monitoring period.
(7) A community water system may apply to the State, in writing (unless the State has waived the requirement for prior State approval), to use only the text specified in paragraph (a)(1) of this section in lieu of the text in paragraphs (a)(1) and (a)(2) of this section and to perform the tasks listed in paragraphs (b)(4) and (b)(5) of this section in lieu of the tasks in paragraphs (b)(2) and (b)(3) of this section if:
(i) The system is a facility, such as a prison or a hospital, where the population served is not capable of or is prevented from making improvements to plumbi ng or installing point of use treatment devices; and
(ii) The system provides water as part of the cost of services provided and does not separately charge for water consumption.

(8) A community water system serving 3,300 or fewer people may limit certain aspects of their public education programs as follows:
(i) With respect to the requirements of paragraph (b)( 2)(vi) of this section, a system serving 3,300 or fewer must implement at least one of the activities listed in that paragraph.
(ii) With respect to the requirements of paragraph (b )(2)(ii) of this section, a system serving 3,300 or fewer people may limit the distribution of the publiceducation materials required under that paragraph to facilities and organizations served bythe system that are most likely to be visited regularly by pregnant women and children.
(iii) With respect to the requirements of paragr aph (b)(2)(v) of this section, the State may waive this requirement for systems serving 3,300 or fewer person s as long as system distributes notices to every household served by the system.
(c) Supplemental monitoring and notification of results. A water system that fails to meet the lead action level on the basis of tap samples collected in accordance with §141.86 shall offer to sample the tap water of any customer who requests it. The system is not required to pay for collecting or analyzing the sample, nor is the system required to collect and analyze the sample itself.

(d) Notification of results —(1) Reporting requirement. All water systems must provide a notice of the individual tap results from lead tap water monitoring carried out under the requirements of §141.86 to the persons served by the water system at the specific sampling site from which the sample was taken (e.g., the occupants of the residence where the tap was tested).

(2) Timing of notification. A water system must provide the consumer notice as soon as practical, but no later than 30 days after the system lear ns of the tap monitoring results.
(3) Content. The consumer notice must include the results of lead tap water monitoring for the tap that was tested, an explanation of the health effects of lead, list steps consumers can take to reduce exposure to lead in drinking water and contact information for the water utility. The notice must also provide the maximum contaminant level goal and the ac tion level for lead and the definitions for these two terms from §141.153(c).
(4) Delivery. The consumer notice must be provided to pe rsons served at the tap that was tested, either by mail or by another method approved by the State. For example, upon approv al by the State, a nontransient non-community water system could post the results on a bulletin board in the facility to allow users to review the information. The system must provide the notice to customers at sample taps tested, including consumers who do not receive water bills.

[72 FR 57815, Oct. 10, 2007]


### § 141.86 Monitoring requirements for lead and copper in tap water.

top
(a) Sample site location. (1) By the applicable date for commenc ement of monitoring under paragraph 

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...(d)(1) of this section, each water system shall comple te a materials evaluation of its distribution system in order to identify a pool of targeted sampling sites that meets the requirements of this section, and which is sufficiently large to ensure that the water sy stem can collect the number of lead and copper tap samples required in paragraph (c) of this section. All sites from which first draw samples are collected shall be selected from this pool of targeted sampling sites. Sampling sites may not include faucets that have point-of-use or point-of-entry treatment devices designed to remove inorganic contaminants.
(2) A water system shall use the information on lead, c opper, and galvanized steel that it is required to collect under §141.42(d) of this part [special monito ring for corrosivity charac teristics] when conducting a materials evaluation. When an evaluation of the information collected pursuant to §141.42(d) is insufficient to locate the requisite number of lead and copper sampling sites that meet the targeting criteria in paragraph (a) of this section, the water system shall review the sources of information listed below in order to identify a sufficient number of sampling sites. In addition, the system shall seek to collect such information where possible in the course of its normal operations (e.g., checking service line materials when reading water meters or performing maintenance activities):
(i) All plumbing codes, permits, and records in the files of the building department(s) which indicate the plumbing materials that are installed within public ly and privately owned structures connected to the distribution system;
(ii) All inspections and records of the distribution system that indic ate the material composition of the service connections that connect a st ructure to the distribution system; and
(iii) All existing water quality information, which incl udes the results of all prior analyses of the system or individual structures connected to the system, indicating lo cations that may be particularly susceptible to high lead or copper concentrations.
(3) The sampling sites selected for a community water system's sampling pool (“tier l sampling sites”) shall consist of single family structures that:
(i) Contain copper pipes with lead solder ins talled after 1982 or contain lead pipes; and/or
(ii) Are served by a lead service line. When multiple -family residences comprise at least 20 percent of the structures served by a water system, the sys tem may include these types of structures in its sampling pool.
(4) Any community water system with insufficient tier 1 sampling sites shall complete its sampling pool with “tier 2 sampling sites”, consisting of build ings, including multiple-family residences that:
(i) Contain copper pipes with lead solder ins talled after 1982 or contain lead pipes; and/or
(ii) Are served by a lead service line.
(5) Any community water system with insufficient tier 1 and tier 2 sampling sites shall complete its sampling pool with “tier 3 sampling sites”, consisting of single family structures that contain copper pipes with lead solder installed before 1983 . A community water system with ins ufficient tier 1, tier 2, and tier 3 sampling sites shall complete its sampling pool with representative sites throughout the distribution system. For the purpose of this paragraph, a representati ve site is a site in which the plumbing materials used at that site would be commonly found at other sites served by the water system.
(6) The sampling sites selected for a non-transient noncommunity water system (“tier l sampling sites”) shall consist of buildings that:

(i) Contain copper pipes with lead solder ins talled after 1982 or contain lead pipes; and/or
(ii) Are served by a lead service line.
(7) A non-transient non-community water system with insufficient tier 1 sites that meet the targeting criteria in paragraph (a)(6) of this section shall complete its sampling pool with sampling sites that contain copper pipes with lead so lder installed before 1983. If additi onal sites are needed to complete the sampling pool, the non-transient non-community water system shall us e representati ve sites throughout the distribution system. For the purpose of this paragraph, a representative site is a site in which the plumbing materials used atthat site would be commonly found at other sites served by the water system.
(8) Any water system whose distribut ion system contains lead service li nes shall draw 50 percent of the samples it collects during each monitoring period from sites that contain lead pipes, or copper pipes with lead solder, and 50 percent of the samples from sites served by a lead service line. A water system that cannot identify a sufficient number of sampling sites serv ed by a lead service line shall collect first-draw samples from all of the sites identified as being served by such lines.
(b) Sample collection methods. (1) All tap samples for lead and copper collected in accordance with this subpart, with the exception of lead service li ne samples collected under §141.84(c) and samples collected under paragraph (b)(5) of this section, shall be first-draw samples.
(2) Each first-draw tap sample for lead and copper shall be one liter in volume and have stood motionless in the plumbing system of each sampling site for at least six hours. First-draw samples from residential housing shall be collected from the cold water kitchen tap or bathroom sink tap. First-draw samples from a nonresidential building shall be one liter in volume and shall be collected at an interiortap from which water is typically drawn for consumption. Non-first-draw samples collected in lieu of firstdraw samples pursuant to paragraph (b)(5) of this section shall be one liter in volume and shall be collected at an interior tap from which water is typically drawn for consumption. First-draw samples may be collected by the system or the system may allow residents to collect first-draw samples after instructing the residents of the sampling procedures sp ecified in this paragraph. To avoid problems of residents handling nitric ac id, acidification of first-draw samples may be done up to 14 days after the sample is collected. After acidificat ion to resolubilize the metals, the sample must stand in the original container for the time specified in the approved EPA method before the sample can be analyzed. If a system allows residents to perform sampling, the system may not challenge, based on alleged errors in sample collection, the accuracy of sampling results.

(3) Each service line sample shall be one liter in volume and have stood motionless in the lead service line for at least six hours. Lead service line sample s shall be collected in one of the following three ways:
(i) At the tap after flushing the volume of water between the tap and the lead service line. The volume of water shall be calculated based on the interior diameter and length of the pipe between the tap and the 

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...lead service line;
(ii) Tapping directly i nto the lead service line; or
(iii) If the sampling site is a building constructed as a single-family residence, allowing the water to run until there is a significant change in temperature which would be indicative of water that has been standing in the lead service line.
(4) A water system shall collect each first draw tap sa mple from the same sampling site from which it collected a previous sample. If, for any reason, the w ater system cannot gain entry to a sampling site in order to collect a follow-up tap sample, the system may collect the follow-up tap sample from another sampling site in its sampling pool as long as the new site meets the same targeting criteria, and is within reasonable proximity of the original site.
(5) A non-transient non-community water system, or a community water system that meets the criteria of §141.85(b)(7), that does not have enough taps that can supply first-draw samples, as defined in §141.2, may apply to the State in writing to substitute non-first-draw samples. Such systems must collect as many first-draw samples from ap propriate taps as possible and identify sampling times and locations that would likely result in the longest standing time for the remaining sites. The State has the discretion to waive the requirement for prior State approval of no n-first-draw sample sites selected by the system, either through State regulation or written notification to the system.
(c) Number of samples. Water systems shall collect at least one sample during each monitoring period specified in paragraph (d) of this section from the nu mber of sites listed in the first column (“standard monitoring”) of the table in this paragraph. A system con ducting reduced monitori ng under paragraph (d) (4) of this section shall collect at least one sample from the number of sites specified in the second column (“reduced monitoring”) of the table in this paragraph during each monitoring period specified in paragraph (d)(4) of this section. Such reduced m onitoring sites shall be representative of the sites required for standard monitoring. A public water sys tem that has fewer than five drinking water taps, that can be used for human consumption meeting the sample site criteria of paragraph (a) of this section to reach the required number of sample sites listed in paragraph (c) of this section, must collect at least one sample from each tap and then must collect additional samples from those taps on different days during the monitoring period to meet the required numb er of sites. Alternatively the State may allow these public water systems to collect a number of samples less than the number of sites specified in paragraph (c) of this section, provided that 100 percent of all taps that can be used for human consumption are sampled. The State must approve this reduction of the minimum number of samples in writing based on a request from the system or ons ite verification by the State. States may specify sampling locations when a system is conducting reduced monitoring. The table is as follows:

(d) Timing of monitoring— (1) Initial tap sampling.
The first six-month monitoring period for small, m edium-size and large systems shall begin on the following dates:

(i) All large systems shall monitor dur ing two consecutive six-month periods.
(ii) All small and medium-size systems shall mo nitor during each six-month monitoring period until:
(A) The system exceeds the lead or copper ac tion level and is therefore required to implement the corrosion control treatment requirements under §141.81, in which case the system shall continue monitoring in accordance with paragraph (d)(2) of this section, or

(B) The system meets the lead and copper action le vels during two consecutive six-month monitoring periods, in which case the system may reduce moni toring in accordance with paragraph (d)(4) of this section.
(2) Monitoring after installation of corrosion control and source water treatment. (i) Any large system which installs optimal corrosion control treatme nt pursuant to §141.81(d)(4) shall monitor during two consecutive six-month monitoring periods by the date specified in §141.81(d)(5).
(ii) Any small or medium-size system which instal ls optimal corrosion control treatment pursuant to §141.81(e)(5) shall monitor during two consecutive si x-month monitoring periods by the date specified in §141.81(e)(6).
(iii) Any system which installs source water treatm ent pursuant to §141.83(a)(3) shall monitor during two consecutive six-month monitoring periods by the date specified in §141.83(a)(4).

(3) Monitoring after State specifies water quality parameter values for optimal corrosion control. After the State specifies the values for water quality control parameters under §141.82(f), the system shall monitor during each subsequent six-month monitoring peri od, with the first monito ring period to begin on the date the State specifies the optimal values under §141.82(f). 

## System size (number of people served) Number of sites (standard monitoring) Number of sites (reduced monitoring) >100,000 100 50 10,001 to 100,000 60 30 3,301 to 10,000 40 20 501 to 3,300 20 10 101 to 500 10 5 ≤ 100 5 5

System size (No. people served) First six-month monitoring period begins on >50,000 January 1, 1992. 3,301 to 50,000 July 1, 1992. ≤ 3,300 July 1, 1993. 

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...(4) Reduced monitoring. (i) A small or medium-size water system that meets the lead and copper action levels during each of two consecutive six-month m onitoring periods may reduce the number of samples in accordance with paragraph (c) of this section, and reduce the frequency of sampling to once per year. Asmall or medium water system collecting fewer than fi ve samples as specified in paragraph (c) of this section, that meets the lead and copper action le vels during each of two consecutive six-month monitoring periods may reduce the frequency of samp ling to once per year. In no case can the system reduce the number of samples required below the minimum of one sample per available tap. This sampling shall begin during the calendar year im mediately following the end of the second consecutive six-month monitoring period.
(ii) Any water system that meets the lead action le vel and maintains the range of values for the water quality control parameters reflecting optimal corrosion control treatment specified by the State under §141.82(f) during each of two consecutive six-m onth monitoring periods may reduce the frequency of monitoring to once per year and reduce the number of lead and copper samples in accordance with paragraph (c) of this section if it receives written approval from the State. This sampling shall begin during the calendar year immediately following the end of the second consecutive six-month monitoring period. The State shall review monitoring, treatment, and other relevant inform ation submitted by the water system in accordance with §141.90, and shall notify the system in writing when it determines the system is eligible to commence re duced monitoring pursuant to this paragraph. The State shall review, and where appropriate, revise its determination when the system submits new monitoring or treatment data, or when other data relevant to the number and frequency of tap sampling becomes available.
(iii) A small or medium-size water system that meets the lead and copper action levels during three consecutive years of monitoring may reduce the frequency of monitoring for lead and copper from annually to once every three years. Any water sys tem that meets the lead action level and maintains the range of values for the water quality control para meters reflecting optimal corrosion control treatment specified by the State under §141.82(f) during three consecutive years of monitoring may reduce the frequency of monitoring from annually to once every th ree years if it receives written approval from the State. Samples collected once every three years shal l be collected no later than every third calendar year. The State shall review monitoring, treatment, an d other relevant information submitted by the water system in accordance with §141.90, and shall notify the system in writing when it determines the system is eligible to reduce the frequency of monitoring to on ce every three years. The State shall review, and where appropriate, revise its determination when the system submits new monitoring or treatment data, or when other data relevant to the number and frequency of tap sampling becomes available.
(iv) A water system that reduces the number and freq uency of sampling shall collect these samples from representative sites included in the pool of targeted sampling sites identified in paragraph (a) of this section. Systems sampling annually or less frequently shall conduct the lead and copper tap sampling during the months of June, July, August, or Sept ember unless the State has approved a different sampling period in accordance with paragraph (d)(4)(iv)(A) of this section.
(A) The State, at its discretion, may approve a different period for conducting the lead and copper tap sampling for systems collecting a reduced number of samples. Such a period shall be no longer than four consecutive months and must represent a time of normal operation where the highest levels of lead are most likely to occur. For a non-transient non-c ommunity water system that does not operate during the months of June through September, and for which the period of normal operation where the highest levels of lead are most likely to occur is not know n, the State shall designate a period that represents a time of normal operation for the system. This samp ling shall begin during the period approved or designated by the State in the calendar year imme diately following the end of the second consecutive six-month monitoring period for systems initiating annual monitoring and during the three-year period following the end of the third consecutive calendar year of annual monitoring for systems initiating triennial monitoring.
(B) Systems monitoring annually, that have been colle cting samples during the months of June through September and that receive State approval to alter their sample collection period under paragraph (d)(4) (iv)(A) of this section, must collect their next roun d of samples during a time period that ends no later than 21 months after the previous round of samp ling. Systems monitoring triennially that have been collecting samples during the months of June thro ugh September, and receive State approval to alter the sampling collection period as per paragraph (d)(4)(iv)(A) of this section, must collect their next round of samples during a time period that ends no later th an 45 months after the previous round of sampling. Subsequent rounds of sampling must be collected annual ly or triennially, as required by this section. Small systems with waivers, granted pursuant to paragr aph (g) of this section, that have been collecting samples during the months of June through September and receive State approval to alter their sample collection period under paragraph (d)(4)(iv)(A) of this section must collect their next round of samples before the end of the 9-year period.
(v) Any water system that demonstrates for two consecutive 6-month monitoring periods that the tap water lead level computed under §141.80(c)(3) is less than or equal to 0.005 mg/L and the tap water copper level computed under §141.80(c)(3) is less than or equal to 0.65 mg/L may reduce the number of samples in accordance with paragraph (c) of this section and reduce the frequency of sampling to once every three calendar years.
(vi)(A) A small or medium-size water system subj ect to reduced monitori ng that exceeds the lead or copper action level shall resume sampling in accordance with paragraph (d)(3) of this section and collect the number of samples specified for standard monitor ing under paragraph (c) of this section. Such a system shall also conduct water quality parameter monitoring in accordance with §141.87(b), (c) or (d) (as appropriate) during the monitoring period in which it exceeded the action level. Any such system may resume annual monitoring for lead and copper at the tap at the reduced number of sites specified in paragraph (c) of this section after it has completed two subsequent consecutive six-month rounds of monitoring that meet the criteria of paragraph (d)(4)(i) of this section and/or may resume triennial monitoring for lead and copper at the reduced number of sites after it demonstrates through subsequent rounds of monitoring that it meets the criteria of either paragraph (d)(4)(iii) or (d)(4)(v) of this section.
(B) Any water system subject to the reduced monitorin g frequency that fails to meet the lead action level during any four-month monitoring period or that fails to o perate at or above the minimum value or within the range of values for the water quality parameters specified by the State under §141.82(f) for more than nine days in any six-month period specified in §141.87(d) shall conduct tap water sampling for lead and copper at the frequency specified in paragraph (d)(3) of this section, collect the number of samples specified for standard monitoring under paragraph (c) of this section, and shall resume monitoring for water quality parameters within the distribution sys tem in accordance with §141.87(d). This standard tap water sampling shall begin no later than the six-month period beginning January 1 of the calendar year following the lead action level exceedance or water quality parameter excursion. Such a system may resume reduced monitoring for lead and copper at the tap and for water quality parameters within the distribution system under the following conditions:

( 1 ) The system may resume annual monitoring for lead and copper at the tap at the reduced number of sites specified in paragraph (c) of this section after ithas completed two subsequent six-month rounds of monitoring that meet the criteria of paragraph (d)(4)(ii) of this section and the system has received written approval from the State that it is appropri ate to resume reduced monitoring on an annual 

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...frequency. This sampling shall begin during the calendar year immediately following the end of the second consecutive six-month monitoring period.
( 2 ) The system may resume triennial monitoring for lead and copper at the tap at the reduced number of sites after it demonstrates through subsequent rounds of monitoring that it meets the criteria of either paragraph (d)(4)(iii) or (d)(4)(v) of this section and the system has received written approval from the State that it is appropriate to resume triennial monitoring.
( 3 ) The system may reduce the number of water quality parameter tap water samples required in accordance with §141.87(e)(1) and the frequency with which it collects such samples in accordance with §141.87(e)(2). Such a system may not resume triennial monitoring for water quality parameters at the tap until it demonstrates, in accordance with the requi rements of §141.87(e)(2), that it has re-qualified for triennial monitoring.
(vii) Any water system subject to a reduced monitor ing frequency under paragraph (d)(4) of this section shall notify the State in writing in accordance with §141.90(a)(3) of any upcoming long-term change in treatment or addition of a new source as described in that section. The State must review and approve the addition of a new source or long-term change in water treatment before it is implemented by the water system. The State may require the system to re sume sampling in accordance with paragraph (d) (3) of this section and collect the number of sample s specified for standard monitoring under paragraph (c) of this section or take other appropriate steps su ch as increased water quality parameter monitoring or re-evaluation of its corrosion control tre atment given the potentially different water quality considerations.
(e) Additional monitoring by systems. The results of any monitoring conducted in addition to the minimum requirements of this section shall be considered by the system and the State in making any determinations ( i.e. , calculating the 90th percentile lead or copper level) under this subpart.

(f) Invalidation of lead or copper tap water samples. A sample invalidated under this paragraph does not count toward determining lead or copper 90th percenti le levels under §141.80(c)(3) or toward meeting the minimum monitoring requirements of paragraph (c) of this section.
(1) The State may invalidate a lead or copper tap water sample at least if one of the following conditions is met.
(i) The laboratory establishes that improper sample analysis caused erroneous results.
(ii) The State determines that the sample was taken from a site that did not meet the site selection criteria of this section.

(iii) The sample container was damaged in transit.
(iv) There is substantial reason to believe that the sample was subject to tampering.
(2) The system must report the results of all sa mples to the State and all supporting documentation for samples the system believes should be invalidated.
(3) To invalidate a sample under paragraph (f)(1) of this section, the decision and the rationale for the decision must be documented in writing. States may not invalidate a sample solely on the grounds that a follow-up sample result is higher or lower than that of the original sample.

(4) The water system must collect replacement samp les for any samples invalidated under this section if, after the invalidation of one or more samples, the system has too few samples to meet the minimum requirements of paragraph (c) of this section. Any su ch replacement samples must be taken as soon as possible, but no later than 20 days after the date the State invalidates the sample or by the end of the applicable monitoring period, whichever occurs later. Replacement samples taken after the end of the applicable monitoring period shall not also be us ed to meet the monitoring requirements of a subsequent monitoring period. The replacement samples shall be taken at the same locations as the invalidated samples or, if that is not possible, at locations other than those already used for sampling during the monitoring period.
(g) Monitoring waivers for small systems. Any small system that meets the criteria of this paragraph may apply to the State to reduce the frequency of monitoring for lead and copper under this section to once every nine years ( i.e., a “full waiver”) if it meets all of the materials criteria specified in paragraph (g)(1) of this section and all of the monitoring criteria specified in paragraph (g)(2) of this section. If State regulations permit, any small system that meets the crit eria in paragraphs (g)(1) and (2) of this section only for lead, or only for copper, may apply to the State for a waiver to reduce the frequency of tap water monitoring to once every nine years for that contaminant only ( i.e., a “partial waiver”).
(1) Materials criteria. The system must demonstrate that its distribution system and service lines and all drinking water supply plumbing, including plumbing conveying drinking water within all residences and buildings connected to the system, are free of le ad-containing materials and/or copper-containing materials, as those terms are defined in this paragraph, as follows:
(i) Lead. To qualify for a full waiver, or a waiver of the tap water monitoring requirements for lead ( i.e., a “lead waiver”), the water system must provide certification and supporting documentation to the State that the system is free of all lead -containing materials, as follows:

(A) It contains no plastic pipes which contain lead plasti cizers, or plastic service lines which contain lead plasticizers; and
(B) It is free of lead service lines, lead pipes, lead soldered pipe joints, and leaded brass or bronze alloy fittings and fixtures, unless such fi ttings and fixtures meet the specific ations of any standard established pursuant to 42 U.S.C. 300g–6(e) (SDWA section 1417(e)).
(ii) Copper. To qualify for a full waiver, or a waiver of the tap water monitoring requirements for copper ( i.e., a “copper waiver”), the water system must provide certification and supporting documentation to the State that the system contains no copper pipes or copper service lines.
(2) Monitoring criteria for waiver issuance. The system must have completed at least one 6-month round of standard tap water monitoring for lead and copp er at sites approved by the State and from the number of sites required by paragraph (c) of this section and demonstrate that the 90th percentile levels for any and all rounds of monitoring conducted sinc e the system became free of all lead-containing and/or copper-containing materials, as appropriate, meet the following criteria. 

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...(i) Lead levels. To qualify for a full waiver, or a lead waiver, the system must demonstrate that the 90th percentile lead level does not exceed 0.005 mg/L.

(ii) Copper levels. To qualify for a full waiver, or a copper waiver, the system must demonstrate that the 90th percentile copper level does not exceed 0.65 mg/L.
(3) State approval of waiver application. The State shall notify the system of its waiver determination, in writing, setting forth the basis of its decision and any condition of the waiver. As a condition of the waiver, the State may require the system to perform sp ecific activities (e.g., limited monitoring, periodic outreach to customers to remind them to avoid ins tallation of materials that might void the waiver) to avoid the risk of lead or copper concentration of co ncern in tap water. The small system must continue monitoring for lead and copper at the tap as required by paragraphs (d)(1) through (d)(4) of this section, as appropriate, until it receives written notification from the State that the waiver has been approved.
(4) Monitoring frequency for systems with waivers. (i) A system with a full waiver must conduct tap water monitoring for lead and copper in accordance with paragraph (d)(4)(iv) of this section at the reduced number of sampling sites identified in paragraph (c) of this section at least once every nine years and provide the materials certification specified in paragraph (g)(1) of this section for both lead and copper to the State along with the monitoring results. Sample s collected every nine years shall be collected no later than every ninth calendar year.
(ii) A system with a partial waiver must conduct tap water monitoring for the waived contaminant in accordance with paragraph (d)(4)(iv) of this section at the reduced number of sampling sites specified in paragraph (c) of this section at least once every nine years and provide the materials certification specified in paragraph (g)(1) of this section pertaining to the waived contaminant along with the monitoring results. Such a system also must c ontinue to monitor for the non-waived contaminant in accordance with requirements of paragraph (d)(1) through (d)(4) of this section, as appropriate.

(iii) Any water system with a full or partial waiver sh all notify the State in writing in accordance with §141.90(a)(3) of any upcoming long-term change in treatment or addition of a new source, as described in that section. The State must review and approve the addition of a new source or long-term change in water treatment before it is implem ented by the water system. The State has the authority to require the system to add or modify waiver conditions (e.g., re quire recertification that the system is free of leadcontaining and/or copper-containing materials, require additional round(s) of monitoring), if it deems such modifications are necessary to address treatment or source water changes at the system.
(iv) If a system with a full or partial waiver becomes aware that it is no longer free of lead-containing or copper-containing materials, as appropriate, (e.g., as a result of new c onstruction or repairs), the system shall notify the State in writing no later than 60 days after becoming aware of such a change.
(5) Continued eligibility. If the system continues to satisfy the requi rements of paragraph (g)(4) of this section, the waiver will be renewed automatically, unless any of the conditions listed in paragraph (g)(5) (i) through (g)(5)(iii) of this section occurs. A syst em whose waiver has been revoked may re-apply for a waiver at such time as it again meets the appropri ate materials and monitoring criteria of paragraphs (g) (1) and (g)(2) of this section.
(i) A system with a full waiver or a lead waiver no lo nger satisfies the materials criteria of paragraph (g) (1)(i) of this section or has a 90th percentile lead level greater than 0.005 mg/L.
(ii) A system with a full waiver or a copper waiver no longer satisfies the materials criteria of paragraph (g)(1)(ii) of this section or has a 90th percentile copper level greater than 0.65 mg/L.
(iii) The State notifies the system, in writing, that the waiver has been revoked, setting forth the basis of its decision.
(6) Requirements following waiver revocation. A system whose full or partial waiver has been revoked by the State is subject to the corrosion control treatment and lead and copper tap water monitoring requirements, as follows:

(i) If the system exceeds the lead and/or copper ac tion level, the system must implement corrosion control treatment in accordance with the deadlines specified in §141.81(e), and any other applicable requirements of this subpart.
(ii) If the system meets both the lead and the copper ac tion level, the system must monitor for lead and copper at the tap no less frequently than once every three years using the reduced number of sample sites specified in paragraph (c) of this section.
(7) Pre-existing waivers. Small system waivers approved by the State in writing prior to April 11, 2000 shall remain in effect under the following conditions:
(i) If the system has demonstrated that it is both free of lead-containing and coppe r-containing materials, as required by paragraph (g)(1) of this section and that its 90th percentile lead levels and 90th percentile copper levels meet the criteria of paragraph (g)(2) of th is section, the waiver remains in effect so long as the system continues to meet the waiver eligibility criteria of paragraph (g)(5) of this section. The first round of tap water monitoring conducted pursuant to paragraph (g)(4) of this section shall be completed no later than nine years after the last time the system has monitored for lead and copper at the tap.
(ii) If the system has met the materials criteria of paragraph (g)(1) of this section but has not met the monitoring criteria of paragraph (g)(2) of this secti on, the system shall conduct a round of monitoring for lead and copper at the tap demonstrating that it meets the criteria of paragraph (g)(2) of this section no later than September 30, 2000. Thereafter, the waiver sha ll remain in effect as long as the system meets the continued eligibility criteria of paragraph (g)(5) of this section. The first round of tap water monitoring conducted pursuant to paragraph (g)(4) of this sectio n shall be completed no later than nine years after the round of monitoring conducted pursuantto paragraph (g)(2) of this section.

[56 FR 26548, June 7, 1991; 56 FR 32113, July 15, 1991; 57 FR 28788, June 29, 1992; as amended at 65 FR 2007, Jan. 12, 2000; 72 FR 57817, Oct. 10, 2007]


### § 141.87 Monitoring requirements for water quality parameters.

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A ll large water systems, and all small- and medium-siz e systems that exceed the lead or copper action level shall monitor water quality parameters in addition to lead and copper in accordance with this 

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...section. The requirements of this section are summarized in the table at the end of this section.
(a) General requirements —(1) Sample collection methods. (i) Tap samples shall be representative of water quality throughout the distributi on system taking into account the number of persons served, the different sources of water, the different treatme nt methods employed by the system, and seasonal variability. Tap sampling under this section is not required to be conducted at taps targeted for lead and copper sampling under §141.86(a). [Note: Systems ma y find it convenient to conduct tap sampling for water quality parameters at sites used fo r coliform sampling under 40 CFR 141.21.]

(ii) Samples collected at the entry point(s) to the di stribution system shall be from locations representative of each source after treatment. If a system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry point to the distribution system during periods of normal operating conditions ( i.e. , when water is representative of all sources being used).

(2) Number of samples. (i) Systems shall collect two tap samples for applicable water quality parameters during each monitoring period specified under paragraphs (b) through (e) of this section from the following number of sites.

(ii) Except as provided in paragraph (c)(3) of this section, systems shall collect two samples for each applicable water quality parameter at each entry poin t to the distribution system during each monitoring period specified in paragraph (b) of this section. During each monitor ing period specified in paragraphs (c)–(e) of this section, systems shall collect one sample for each applicable water quality parameter at each entry point to the distribution system.
(b) Initial sampling All large water systems shall measure the applicable water quality parameters as specified below at taps and at each entry point to the distribution system during each six-month monitoring period specified in §141.86(d)(1). All small and medium-size systems shall measure the applicable water quality parameters at the locations specified below during each six-month monitoring period specified in §141.86(d)(1) during which the system exceeds the lead or copper action level.
(1) At taps:
(i) pH;

(ii) Alkalinity;
(iii) Orthophosphate, when an inhibitor containing a phosphate compound is used;
(iv) Silica, when an inhibitor contai ning a silicate compound is used;
(v) Calcium;
(vi) Conductivity; and
(vii) Water temperature.

(2) At each entry point to the distribution system: all of the applicable parameters listed in paragraph (b) (1) of this section.
(c) Monitoring after installation of corrosion control. Any large system which installs optimal corrosion control treatment pursuant to §141.81(d)(4) shall measure the water quality parameters at the locations and frequencies specified below during each six-m onth monitoring period specified in §141.86(d)(2)(i). A ny small or medium-size system which installs o ptimal corrosion control treatment shall conduct such monitoring during each six-month monitoring period specified in §141.86(d)(2)(ii) in which the system exceeds the lead or copper action level.
(1) At taps, two samples for:
(i) pH;
(ii) Alkalinity;
(iii) Orthophosphate, when an inhibitor containing a phosphate compound is used;
(iv) Silica, when an inhibitor contai ning a silicate compound is used;
(v) Calcium, when calcium carbonate stabilizati on is used as part of corrosion control.

(2) Except as provided in paragraph (c)(3) of this sect ion, at each entry point to the distribution system, at least one sample no less frequently than every two weeks (biweekly) for:
(i) pH;
(ii) When alkalinity is adjusted as part of optimal corrosion control, a reading of the dosage rate of the chemical used to adjust alkalinity, and the alkalinity concentration; and
(iii) When a corrosion inhibitor is used as part of optimal corrosion control, a reading of the dosage rate 

## System size (No. people served) No. of sites for water quality parameters >100,000 25 10,001–100,000 10 3,301 to 10,000 3 501 to 3,300 2 101 to 500 1 ≤ 100 1 

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...of the inhibitor used, and the concentration of orthophos phate or silica (whichever is applicable).
(3) Any ground water system can limit entry point sampling described in paragraph (c)(2) of this section to those entry points that are representative of wate r quality and treatment conditions throughout the system. If water from untreated ground water sources mixes with water from treated ground water sources, the system must monitor for water quality parameters both at representative entry points receiving treatment and representative entry points receiving no treatment. Prior to the start of any monitoring under this paragraph, the system shall provide to the State wr itten information identifying the selected entry points and documentation, including i nformation on seasonal va riability, sufficient to demonstrate that the sites are representative of water quality and treatment conditions throughout the system.
(d) Monitoring after State specifies water quality parameter values for optimal corrosion control . After the State specifies the values for applicable water q uality control parameters reflecting optimal corrosion control treatment under §141.82(f), all large systems shall measure the applicable water quality parameters in accordance with paragraph (c) of this section and determine compliance with the requirements of §141.82(g) every six months with the first six-month period to begin on either January 1 or July 1, whichever comes first, after the State specifies the optimal values under §141.82(f). Any small or medium-size system shall conduct such monito ring during each six-month period specified in thisparagraph in which the system exceeds the lead or copper action level. For any such small and mediumsize system that is subject to a reduced monitoring frequency pursuant to §141.86(d)(4) at the time of the action level exceedance, the start of the applicable six-month monitoring period under this paragraph shall coincide with the start of the applicable moni toring period under §141.86(d)(4). Compliance with State-designated optimal water quality parameter values shall be determined as specified under §141.82 (g).
(e) Reduced monitoring. (1) Any water system that maintains the range of values for the water quality parameters reflecting optimal corros ion control treatment during each of two consecutive six-month monitoring periods under paragraph (d) of this sect ion shall continue monitorin g at the entry point(s) to the distribution system as specified in paragraph (c)(2) of this section. Such system may collect two tap samples for applicable water quality parameters from the following reduced number of sites during each six-month monitoring period.

(2)(i) Any water system that maintains the range of va lues for the water quality parameters reflecting optimal corrosion control treatment specified bythe State under §141.82(f) during three consecutive years of monitoring may reduce the frequency with which it collects the number of tap samples for applicable water quality parameters specified in this paragraph (e)(1) of this section from every six months to annually. This sampling begins during the calendar year immediately following the end of the monitoring period in which the third consecutive year of six-month monitoring occurs. Any water system that maintains the range of values for the water qua lity parameters reflecting optimal corrosion control treatment specified by the State under §141.82(f), during three consecutive years of annual monitoring under this paragraph may reduce the frequency with which it collects the number of tap samples for applicable water quality parameters specified in paragraph (e)(1) of this section from annually to every three years. This sampling begins no later than the third calendar year following the end of the monitoring period in which the third co nsecutive year of monitoring occurs.
(ii) A water system may reduce the frequency with which it collects tap samples for applicable water quality parameters specified in paragraph (e)(1) of this section to every three years if it demonstrates during two consecutive monitoring periods that its tap water lead level at the 90th percentile is less than or equal to the PQL for lead specified in §141.89 (a)(1)(ii), that its tap water copper level at the 90th percentile is less than or equal to 0.65 mg/L for co pper in §141.80(c)(2), and that it also has maintained the range of values for the water quality parameters reflecting optimal corrosion control treatment specified by the State under §141.82(f). Monitoring conducted every three years shall be done no later than every third calendar year.
(3) A water system that conducts sampling annually shall collect these samples evenly throughout the year so as to reflect seasonal variability.

(4) Any water system subject to the reduced monitoring frequency that fails to operate at or above the minimum value or within the range of values for the water quality parameters specified by the State in §141.82(f) for more than nine days in any six-month period specified in §141.82(g) shall resume distribution system tap water sampling in accordance with the number and frequency requirements in paragraph (d) of this section. Such a system may resume annual monitoring for water quality parameters at the tap at the reduced number of sites specified in paragraph (e)(1) of this section after it has completed two subsequent consecutive six-month roun ds of monitoring that meet the criteria of that paragraph and/or may resume triennial monitoring for water quality parameters at the tap at the reduced number of sites after it demonstrates through subseque nt rounds of monitoring that it meets the criteria of either paragraph (e)(2)(i) or (e)(2)(ii) of this section.
(f) Additional monitoring by systems. The results of any monitoring conducted in addition to the minimum requirements of this section shall be considered by the system and the State in making any determinations ( i.e. , determining concentrations of water quality parameters) under this section or §141.82.

Summary of Monitoring Requirements for Water Quality Parameters 1



## System size (No. of people served) Reduced No. of sites for water quality parameters >100,000 10 10,001 to 100,000 7 3,301 to 10,000 3 501 to 3,300 2 101 to 500 1 ≤ 100 1

Monitoring

period Parameters 2 

## Location Frequency Initial monitoring pH, alkalinity, orthophosphate or silica 3



## , calcium, conductivity, Taps and at entry point(s) to distribution Every 6 months. 

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...1 Table is for illustrative purposes; consult the textof this section for precise regulatory requirements.

2 Small and medium-size systems have to monitor for water quality parameters only during monitoring periods in which the system exceeds the lead or copper action level.

3 Orthophosphate must be measured only when an inhibitor containing a phos phate compound is used. Silica must be measured only when an inhibitor containing silicate compound is used.

4 Calcium must be measured only when calcium carb onate stabilization is used as part of corrosion control.

5 Inhibitor dosage rates and inhi bitor residual concen trations (orthophosphate or silica) must be measured only when an inhibitor is used.

6 Ground water systems may limit monitoring to representative locations throughout the system.

7 Water systems may reduce frequency of monitoring for water quality parameters at the tap from every six months to annually if they have maintained the ran ge of values for water quality parameters reflecting optimal corrosion control during 3 consecutive years of monitoring.

8 Water systems may further reduce the frequency of monitoring for water quality parameters at the tap from annually to once every 3 years if they have maintained the range of values for water quality parameters reflecting optimal corros ion control during 3 c onsecutive years of an nual monitoring. Water systems may accelerate to triennial monitoring for water quality parameters at the tap if they have maintained 90th percentile lead levels less than or eq ual to 0.005 mg/L, 90th percentile copper levels less than or equal to 0.65 mg/L, and the range of water quality parameters designated by the State under §141.82(f) as representing optimal corrosion control during two consecuti ve six-month monitoring periods.

[56 FR 26548, June 7, 1991; 57 FR 28788, June 29, 1992, as amended at 59 FR 33862, June 30, 1994; 65 FR 2010, Jan. 12, 2000; 72 FR 57818, Oct. 10, 2007]


### § 141.88 Monitoring requirements for lead and copper in source water.

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(a) Sample location, collection methods, and number of samples. (1) A water system that fails to meet the lead or copper action level on the basis of tap samples collected in accordance with §141.86 shall collect lead and copper source water samples in ac cordance with the following requirements regarding sample location, number of samples, and collection methods:
(i) Groundwater systems shall take a minimum of on e sample at every entry point to the distribution system which is representative of each well after treatment (hereafter called a sampling point). The system shall take one sample at the same sampli ng point unless conditions make another sampling point more representative of each source or treatment plant. 

## temperature system After installation of corrosion control pH, alkalinity, orthophosphate or silica 3



## , calcium 4 

## Taps Every 6 months.

pH, alkalinity, dosage rate and concentration (if alkalinity adjusted as part of corrosion control), inhibitor dosage rate and inhibitor residual 5 

## Entry point(s) to distribution system 6 

## No less frequently than every two weeks.

After State specifies parameter values for optimal corrosion control pH, alkalinity, orthophosphate or silica 3



## , calcium 4 

## Taps Every 6 months.

pH, alkalinity dosage rate and concentration (if alkalinity adjusted as part of corrosion control), inhibitor dosage rate and inhibitor residual 5 

## Entry point(s) to distribution system 6 

## No less frequently than every two weeks.

Reduced monitoring pH, alkalinity, orthophosphate or silica 3



## , calcium 4 

## Taps Every 6 months, annually 7 

## or every 3 years 8 

## ; reduced number of sites. pH, alkalinity dosage rate and concentration (if alkalinity adjusted as part of corrosion control), inhibitor dosage rate and inhibitor residual 5 

## Entry point(s) to distribution system 6 

## No less frequently than every two weeks. 

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...(ii) Surface water systems shall take a minimum of on e sample at every entry point to the distribution system after any application of treatment or in the di stribution system at a point which is representative of each source after treatment (hereafter called a sampling point). The system shall take each sample at the same sampling point unless conditions make another sampling point more representative of each source or treatment plant.


### Note to paragraph (a)(1)(ii): For the purposes of this paragraph, surface water systems include systems with a combination of surface and ground sources.

(iii) If a system draws water from more than one source and the sources are combined before distribution, the system must sample at an entry po int to the distribution system during periods of normal operating conditions ( i.e., when water is representative of all sources being used).
(iv) The State may reduce the total number of samp les which must be analyzed by allowing the use of compositing. Compositing of samples must be done by certified laboratory personnel. Composite samples from a maximum of five samples are allowed, provided that if the lead concentration in the composite sample is greater than or equal to 0.001 m g/L or the copper concentration is greater than or equal to 0.160 mg/L, then either:
(A) A follow-up sample shall be taken and analyzed wi thin 14 days at each sampling point included in the composite; or
(B) If duplicates of or sufficient qua ntities from the original samples from each sampling point used in the composite are available, the system may use these instead of resampling.

(2) Where the results of sampling indicate an exceedance of maximum permissible source water levels established under §141.83(b)(4), the State may require that one additional sample be collected as soon as possible after the initial sample was taken (but not to exceed two weeks) at the same sampling point. If a State-required confirmation sample is taken for lead or copper, then the results of the initial and confirmation sample shall be averaged in determin ing compliance with the State-specified maximum permissible levels. Any sample value below the detection limit shall be considered to be zero. Any value above the detection limit but below the PQL shall either be considered as the measured value or be considered one-half the PQL.
(b) Monitoring frequency after system exceeds tap water action level. Any system which exceeds the lead or copper action level at the tap shall collect one source water sample from each entry point to the distribution system no later than six months after th e end of the monitoring period during which the lead or copper action level was exceeded. For monitoring periods that are annual or less frequent, the end of the monitoring period is September 30 of the calendar year in which the sampling occurs, or if the State has established an alternate monitoring period, the last day of that period.
(c) Monitoring frequency after installation of source water treatment. Any system which installs source water treatment pursuant to §141.83(a)(3) shall collectan additional source water sample from each entry point to the distribution system during two c onsecutive six-month moni toring periods by the deadline specified in §141.83(a)(4).
(d) Monitoring frequency after State specifies maximum per missible source water levels or determines that source water treatment is not needed. (1) A system shall monitor at the frequency specified below in cases where the State specifies maximum permissible source water levels under §141.83(b)(4) or determines that the system is not required to install source water treatment under §141.83(b)(2).

(i) A water system using only groundwater shall collect samples once during the three-year compliance period (as that term is defined in §141.2) in effect when the applicable State determination under paragraph (d)(1) of this section is made. Such systems shall collect samples once during each subsequent compliance period. Triennial samples shall be collected every third calendar year.
(ii) A water system using surface water (or a comb ination of surface and ground water) shall collect samples once during each calendar year, the first a nnual monitoring period to begin during the year in which the applicable State determination is m ade under paragraph (d)(1) of this section.
(2) A system is not required to conduct source water sampling for lead and/or copper if the system meets the action level for the specific contaminant in tap water samples during the entire source water sampling period applicable to the system under paragraph (d)(1) (i) or (ii) of this section.
(e) Reduced monitoring frequency. (1) A water system using only ground water may reduce the monitoring frequency for lead and copper in source water to once during eac h nine-year compliance cycle (as that term is defined in §141.2) provided that the samples are collected no later than every ninth calendar year and if the system meets one of the following criteria:
(i) The system demonstrates that finished drinki ng water entering the distribution system has been maintained below the maximum permissible lead and coppe r concentrations specified by the State in §141.83(b)(4) during at least thr ee consecutive compliance periods under paragraph (d)(1) of this section; or
(ii) The State has determined that source water treatment is not needed and the system demonstrates that, during at least three consecuti ve compliance periods in which sampling was conducted under paragraph (d)(1) of this section, the concentration of lead in source water was less than or equal to 0.005 mg/L and the concentration of copper in source water was less than or equal to 0.65 mg/L.
(2) A water system using surface water (or a co mbination of surface water and ground water) may reduce the monitoring frequency in paragraph (d)(1) of this section to once during each nine-year compliance cycle (as that term is defined in §141.2) provided that the samples are collected no later than every ninth calendar year and if the system meets one of the following criteria:
(i) The system demonstrates that finished drinki ng water entering the distribution system has been maintained below the maximum permissible lead and coppe r concentrations specified by the State in §141.83(b)(4) for at least three consecutive years; or
(ii) The State has determined that source water treatment is not needed and the system demonstrates that, during at least three c onsecutive years, the concentration of lead in source water was less than or equal to 0.005 mg/L and the concentration of copper in source water was less than or equal to 0.65 mg/L.

(3) A water system that uses a new source of water is not eligible for reduced monitoring for lead and/or copper until concentrations in samples collected from the new source during three consecutive 

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...monitoring periods are below the maximum permissible l ead and copper concentrations specified by the State in §141.83(a)(5).

[56 FR 26548, June 7, 1991; 57 FR 28788 and 28789, June 29, 1992, as amended at 65 FR 2012, Jan. 12, 2000; 72 FR 57819, Oct. 10, 2007]


### § 141.89 Analytical methods.

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(a) Analyses for lead, copper, pH, conductivity, calcium, alkalinity, orthophosphate, silica, and temperature shall be conducted with the methods in §141.23(k)(1).
(1) Analyses for alkalinity, calcium, conductivi ty, orthophosphate, pH, silica, and temperature may be performed by any person acceptable to the State. Analyses under this section for lead and copper shall only be conducted by laboratories that have been certified by EPA or the State. To obtain certification to conduct analyses for lead and copper, laboratories must:
(i) Analyze Performance Evaluation samples, which include lead and copper, provided by or acceptable to EPA or the State at least once a year by each method for which the laboratory desires certification; and
(ii) Achieve quantitative acceptance limits as follows:

(A) For lead: ±30 percent of the actual amount in the Performance Evaluation sample when the actual amount is greater than or equal to 0.005 mg/L. The Prac tical Quantitation Level, or PQL for lead is 0.005 mg/L.
(B) For Copper: ±10 percent of the actual amount in the Performance Evaluation sample when the actual amount is greater than or equal to 0.050 mg/L. The Practical Quantitation Level, or PQL for copper is 0.050 mg/L.
(iii) Achieve the method detection limit for lead of 0.001 mg/L according to the procedures in appendix B of part 136 of this title. This need only be accomplished if the laboratory will be processing source water composite samples under §141.88(a)(1)(iv).
(iv) Be currently certified by EPA or the State to perform analyses to the specifications described in paragraph (a)(1) of this section.

(2) States have the authority to allow the use of previously collected monitoring data for purposes of monitoring, if the data were collected and analyzed in accordance with the requirements of this subpart.
(3) All lead and copper levels measured between the PQL and MDL must be either reported as measured or they can be reported as one-half the PQL specified for lead and copper in paragraph (a)(1) (ii) of this section. All levels below the lead and copper MDLs must be reported as zero.
(4) All copper levels measured between the PQL and the MDL must be either reported as measured or they can be reported as one-half the PQL (0.025 mg/L). All levels below the copper MDL must be reported as zero.
(b) [Reserved]

[56 FR 26548, June 7, 1991, as amended at 57 FR 28789, June 29, 1992; 57 FR 31847, July 17, 1992; 59 FR 33863, June 30, 1994; 59 FR 62470, Dec. 5, 1994; 64 FR 67466, Dec. 1, 1999; 65 FR 2012, Jan. 12, 2000; 72 FR 57819, Oct. 10, 2007]


### § 141.90 Reporting requirements.

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A ll water systems shall report all of the following inform ation to the State in accordance with this section.
(a) Reporting requirements for tap water monitoring for lead and copper and for water quality parameter monitoring. (1) Except as provided in paragraph (a)(1)(viii) of this section, a water system shall report the information specified below for all tap water samples specified in §141.86 and for all water quality parameter samples specified in §141.87 within the first 10 days following the end of each applicable monitoring period specified in §141.86 and §141.87 ( i.e., every six months, annually, every 3 years, or every 9 years). For monitoring periods with a dur ation less than six months, the end of the monitoring period is the last date samples can be collected du ring that period as specifi ed in §§141.86 and 141.87.

(i) The results of all tap samples for lead and copper including the location of each site and the criteria under §141.86(a) (3), (4), (5), (6), and/or (7) under which the site was selected for the system's sampling pool;
(ii) Documentation for each tap water lead or copper sample for which the water system requests invalidation pursuant to §141.86(f)(2);
(iii) [Reserved]
(iv) The 90th percentile lead and copper concentrations me asured from among all lead and copper tap water samples collected during each monitoring period (calculated in accordance with §141.80(c)(3)), unless the State calculates the system's 90th percentile lead and copper levels under paragraph (h) of this section;
(v) With the exception of initial tap sampling c onducted pursuant to §141.86(d)(1), the system shall designate any site which was not sampled during previous monitoring periods, and include an explanation of why sampling sites have changed;

(vi) The results of all tap samples for pH, and wher e applicable, alkalinity, calcium, conductivity, temperature, and orthophosphate or silica collected under §141.87 (b)–(e); 

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...(vii) The results of all samples collected at the entry point(s) to the distribution system for applicable water quality parameters under §141.87 (b)–(e);

(viii) A water system shall report the results of all water quality parameter samples collected under §141.87(c) through (f) during each six-month monitor ing period specified in §141.87(d) within the first 10 days following the end of the monitoring period unless the State has specified a more frequent reporting requirement.
(2) For a non-transient non-community water system, or a community water sys tem meeting the criteria of §141.85(b)(7), that does not have enough taps that can provide first-draw samples, the system must either:
(i) Provide written documentation to the State identi fying standing times and locations for enough nonfirst-draw samples to make up its sampling pool under §141.86(b)(5) by the start of the first applicable monitoring period under §141.86(d) that commences after April 11, 2000, unless the State has waived prior State approval of non-first-draw sample sites selected by the system pursuant to §141.86(b)(5); or
(ii) If the State has waived prior approval of non-first-d raw sample sites selected by the system, identify, in writing, each site that did not meet the six-hour minimum standing time and the length of standing time for that particular substitute sample collected purs uant to §141.86(b)(5) and include this information with the lead and copper tap sample results required to be submitted pursuant to paragraph (a)(1)(i) of this section.
(3) At a time specified by the Stat e, or if no specific time is desi gnated by the State, then as early as possible prior to the addition of a new source or any long-term change in water treatment, a water system deemed to have optimized corrosion control under §141.81(b) (3), a water system subject to reduced monitoring pursuant to §141.86(d)(4), or a water system subject to a monitoring waiver pursuant to §141.86(g), shall submit written docume ntation to the State describing the change or addition. The State must review and approve the addition of a new source or long-term change in treatment before it is implemented by the water system. Examples of long-term treatment changes include the addition of a new treatment process or modification of an existing treatment process. Examples of modifications include switching sec ondary disinfectants, switching coagulants (e.g., alum to ferric chloride), and switching corrosion inhibitor products (e.g., orthophosphate to blended phosphate). Long-term changes can include dose changes to existing chemicals if the system is planning long-term changes to its finished water pH or residual inhi bitor concentration. Long-term treatment changes would not include chemical dose fluctuations associated with daily raw water quality changes.

(4) Any small system applying for a monitoring waiv er under §141.86(g), or subject to a waiver granted pursuant to §141.86(g)(3), shall provide the following i nformation to the State in writing by the specified deadline:
(i) By the start of the first applicable monitoring per iod in §141.86(d), any small water system applying for a monitoring waiver shall provi de the documentation required to demonstrate that it meets the waiver criteria of §§141.86(g)(1) and (2).
(ii) No later than nine years after the monitoring previously conducted purs uant to §141.86(g)(2) or §141.86(g)(4)(i), each small system desiring to main tain its monitoring waiver shall provide the information required by §§141.86(g)(4)(i) and (ii).
(iii) No later than 60 days after it becomes aware that it is no longer free of lead-containing and/or copper-containing material, as ap propriate, each small system with a monitoring waiver shall provide written notification to the State, setti ng forth the circumstances resulting in the lead-containing and/or copper-containing materials being i ntroduced into the system and what corrective action, if any, the system plans to remove these materials.
(iv) By October 10, 2000, any small system with a waiver granted prior to April 11, 2000 and that has not previously met the requirements of §141.86(g)(2) shall provide the information required by that paragraph.
(5) Each ground water system that limits water qualit y parameter monitoring to a subset of entry points under §141.87(c)(3) shall provide, by the commenc ement of such monitoring, written correspondence to the State that identifies the selected entry points an d includes information suffic ient to demonstrate that the sites are representative of water quality a nd treatment conditions throughout the system.
(b) Source water monitoring reporting requirements. (1) A water system shall report the sampling results for all source water samples collected in accordance with §141.88 within the first 10 days following the end of each source water monitoring period ( i.e. , annually, per compliance period, per compliance cycle) specified in §141.88.
(2) With the exception of the first round of source water sampling conducted pursuant to §141.88(b), the system shall specify any site which was not sampled during previous monitoring periods, and include an explanation of why the sampling point has changed.

(c) Corrosion control treatment reporting requirements. By the applicable dates under §141.81, systems shall report the following information:
(1) For systems demonstrating that they have alreadyoptimized corrosion control, information required in §141.81(b) (2) or (3).
(2) For systems required to optimize corrosion control, their recommendation regarding optimal corrosion control treatment under §141.82(a).
(3) For systems required to evaluate the effectiveness of corrosion control treatments under §141.82(c), the information required by that paragraph.

(4) For systems required to install optimal corrosion control designated by the State under §141.82(d), a letter certifying that the system has completed installing that treatment.
(d) Source water treatment reporting requirements. By the applicable dates in §141.83, systems shall provide the following information to the State:
(1) If required under §141.83(b)(1), their recommendation regarding source water treatment;
(2) For systems required to install source water treatm ent under §141.83(b)(2), a letter certifying that the 

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...system has completed installing the treatment des ignated by the State within 24 months after the State designated the treatment.
(e) Lead service line replacement reporting requirements. Systems shall report the following information to the State to demonstrate compliance with the requirements of §141.84:
(1) No later than 12 months after the end of a moni toring period in which a system exceeds the lead action level in sampling referred to in §141.84(a), the system must submit written documentation to the State of the material evaluation conducted as required in §141.86(a), identify the initial number of lead service lines in its distribution system at the time th e system exceeds the lead action level, and provide the system's schedule for annually replacing at least 7 percent of the initial number of lead service lines in its distribution system.
(2) No later than 12 months after the end of a moni toring period in which a system exceeds the lead action level in sampling referred to in §141.84(a), and every 12 months thereafter, the system shall demonstrate to the State in writing that the system has either:
(i) Replaced in the previous 12 mo nths at least 7 percent of the init ial lead service lines (or a greater number of lines specified bythe State under §141.84(e)) in its distribution system, or
(ii) Conducted sampling which demonstrates that the l ead concentration in all service line samples from an individual line(s), taken pursuant to §141.86(b)(3), is less than or equal to 0.015 mg/L. In such cases, the total number of lines replaced and/or which meet the criteria in §141.84(c) shall equal at least 7 percent of the initial number of lead lines identified under paragraph (e)(1) of this section (or the percentage specified by the State under §141.84(e)).
(3) The annual letter submitted to the State under paragraph (e)(2) of this section shall contain the following information:

(i) The number of lead service lines scheduled to be replaced during the previous year of the system's replacement schedule;
(ii) The number and location of each lead service line replaced during the previ ous year of the system's replacement schedule;
(iii) If measured, the water lead concentration and lo cation of each lead service line sampled, the sampling method, and the date of sampling.
(4) Any system which collects lead service line sa mples following partial lead service line replacement required by §141.84 shall report the results to the State within the first ten days of the month following the month in which the system receives the laboratory results, or as specified by the State. States, at their discretion may eliminate this requirement to repo rt these monitoring results. Systems shall also report any additional information as specified by the State, and in a time and manner prescribed by the State, to verify that all partial lead service line replacement activiti es have taken place.
(f) Public education program reporting requirements. (1) Any water system that is subject to the public education requirements in §141.85 shall, within ten days after the end of each period in which the system is required to perform public education in accordance with §141.85(b), send written documentation to the State that contains:
(i) A demonstration that the system has delivered the public education materials that meet the content requirements in §141.85(a) and the delivery requirements in §141.85(b); and

(ii) A list of all the newspapers, radio stations, tel evision stations, and facili ties and organizations to which the system delivered public education materials during the period in which the system was required to perform public education tasks.

(2) Unless required by the State, a system that pr eviously has submitted the information required by paragraph (f)(1)(ii) of this section need not resubmit the information required by paragraph (f)(1)(ii) of this section, as long as there have been no changes in the distribution list and the system certifies that the public education materials were dist ributed to the same list submitted previously.
(3) No later than 3 months following the end of the monitoring period, each system must mail a sample copy of the consumer notification of tap results to the State along with a certification that the notification has been distributed in a manner consis tent with the requirements of §141.85(d).
(g) Reporting of additional monitoring data. Any system which collects sampling data in addition to that required by this subpart shall report the results to the State within the first ten days following the end of the applicable monitoring period under §§141.86, 141.87 and 141.88 during which the samples are collected.
(h) Reporting of 90th percentile lead and copper concentrations where the State calculates a system's 90th percentile concentrations. A water system is not required to report the 90th percentile lead and copper concentrations measured from among all lead and copper tap water samples collected during each monitoring period, as required by pa ragraph (a)(1)(iv) of this section if:
(1) The State has previously notifi ed the water system that it will calculate the water system's 90th percentile lead and copper concentrations, based on th e lead and copper tap results submitted pursuant to paragraph (h)(2)(i) of this section, and has specified a date before the end of the applicable monitoring period by which the system must provide the results of lead and copper tap water samples;
(2) The system has provided the fol lowing information to the State by the date specified in paragraph (h) (1) of this section:

(i) The results of all tap samples for lead and copper including the location of each site and the criteria under §141.86(a)(3), (4), (5), (6), and/or (7) under which the site was selected for the system's sampling pool, pursuant to paragraph (a)(1)(i) of this section; and

(ii) An identification of sampling sites utilized during the current monitoring period that were not sampled during previous monitoring periods, and an ex planation why sampling sites have changed; and
(3) The State has provided the results of the 90th percentile lead and copper calculations, in writing, to the water system before the end of the monitoring period. 

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...[56 FR 26548, June 7, 1991; 57 FR 28789, June 29, 1992, as amended at 59 FR 33864, June 30, 1994; 65 FR 2012, Jan. 12, 2000; 72 FR 57819, Oct. 10, 2007]


### § 141.91 Recordkeeping requirements.

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A ny system subject to the requirements of this subpart shall retain on its premises original records of all sampling data and analyses, reports, surveys, le tters, evaluations, schedules, State determinations, and any other information required by §§141.81 through 141.88. Each water system shall retain the records required by this section for no fewer than 12 years.


### Subpart J—Use of Non-Centralized Treatment Devices

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### Source: 52 FR 25716, July 8, 1987, unless otherwise noted.
§ 141.100 Criteria and procedures for public water systems using point-of-entry devices.

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(a) Public water systems may use point-of-entry devices to comply with maximum contaminant levels only if they meet the requirements of this section.
(b) It is the responsibility of the public water system to operate and maintain the point-of-entry treatment system.
(c) The public water system must develop and obtain State approval for a monitoring plan before pointof-entry devices are installed for compliance. Under the plan approved by the State, point-of-entry devices must provide health protection equivalentto central water treatment. “Equivalent” means that the water would meet all national primary drinking w ater regulations and would be of acceptable quality similar to water distributed by a well-operated cent ral treatment plant. In addition to the VOCs, monitoring must include physical measurements and observations such as total flow treated and mechanical condition of th e treatment equipment.
(d) Effective technology must be properly app lied under a plan approved by the State and the microbiological safety of the water must be maintained.

(1) The State must require adequate certification of performance, field testing, and, if not included in the certification process, a rigorous engineering design review of the point-of-entry devices.
(2) The design and application of the point-of-entry devi ces must consider the tendency for increase in heterotrophic bacteria concentrations in water treated with activated carbon. It may be necessary to use frequent backwashing, post-contactor disinfection, and Heterotrophic Plate Count monitoring to ensure that the microbiological safety of the water is not compromised.
(e) All consumers shall be protected. Every building connected to the system must have a point-of-entry device installed, maintained, and adequately monitored. The State must be assured that every building is subject to treatment and monitoring , and that the rights and responsibilities of the public water system customer convey with title upon sale of property.

[52 FR 25716, July 8, 1987; 53 FR 25111, July 1, 1988]


### § 141.101 Use of bottled water.

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Public water systems shall not use bottled water to ac hieve compliance with an MCL. Bottled water may be used on a temporary basis to avoid unreasonable risk to health.

[63 FR 31934, June 11, 1998]


### Subpart K—Treatment Techniques

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### Source: 56 FR 3594, Jan. 30, 1991, unless otherwise noted.
§ 141.110 General requirements.

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The requirements of subpart K of this part constitute na tional primary drinking water regulations. These regulations establish treatment techniques in li eu of maximum contaminant levels for specified contaminants.


### § 141.111 Treatment techniques for acrylamide and epichlorohydrin.

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Each public water system must certify annually in writing to the State (using third party or manufacturer's certification) that when acrylamide and epichlorohydrin are used in drinking water systems, the combination (or product) of dose and monomer leve l does not exceed the levels specified as follows: 

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...

### A crylamide=0.05% dosed at 1 ppm (or equivalent)
Epichlorohydrin=0.01% dosed at 20 ppm (or equivalent)

Certifications can rely on manufacturers or third parties, as approved by the State.


### Subpart L—Disinfectant Residuals, Disinfection Byproducts, and Disinfection Byproduct Precursors

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### § 141.130 General requirements.

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(a) The requirements of this subp art L constitute national prim ary drinking water regulations.
(1) The regulations in this subpart establish criter ia under which community water systems (CWSs) and nontransient, noncommunity water systems (NTNCW Ss) which add a chemical disinfectant to the water in any part of the drinking water treatment proc ess must modify their practices to meet MCLs and MRDLs in §§141.64 and 141.65, respectively, and mu st meet the treatment technique requirements for disinfection byproduct precursors in §141.135.
(2) The regulations in this subpart establish criter ia under which transient NCWSs that use chlorine dioxide as a disinfectant or oxidant mu st modify their practices to meet the MRDL for chlorine dioxide in §141.65.
(3) EPA has established MCLs for TTHM and HAA5 and treatment technique requirements for disinfection byproduct precursors to limit the levels of known and unknown disinfection byproducts which may have adverse health effects. These disi nfection byproducts may include chloroform; bromodichloromethane; dibromochloromethane; bromoform; dichloroacetic acid; an d trichloroacetic acid.
(b) Compliance dates —(1) CWSs and NTNCWSs. Unless otherwise noted, systems must comply with the requirements of this subpart as follows. Subpart H systems serving 10,000 or more persons must comply with this subpart beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not und er the direct influence of surface water must comply with this subpart beginning January 1, 2004.
(2) Transient NCWSs. Subpart H systems serving 10,000 or more persons and using chlorine dioxide as a disinfectant or oxidant must comply with any r equirements for chlorine dioxide in this subpart beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and using chlorine dioxide as a disinfectant or oxidant and systems using onlyground water not under the direct influence of surface water and using chlori ne dioxide as a disinfectant or oxidant must comply with any requirements for chlorine dioxide in this subpart beginning January 1, 2004.
(c) Each CWS and NTNCWS regulated under paragr aph (a) of this section must be operated by qualified personnel who meet the requirements specified by the State and are included in a State register of qualified operators.
(d) Control of disinfectant residuals. Notwithstanding the MRDLs in §141.65, systems may increase residual disinfectant levels in the distri bution system of chlorine or chlo ramines (but not chlorine dioxide) to a level and for a time necessary to protect publ ic health, to address specific microbiological contamination problems caused by circumstances such as, but not limi ted to, distribution line breaks, storm run-off events, source water contaminat ion events, or cros s-connection events.

[63 FR 69466, Dec. 16, 1998, as amended at 66 FR 3776, Jan. 16, 2001]


### § 141.131 Analytical requirements.

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(a) General. (1) Systems must use only the analytical methods specified in this section, or their equivalent as approved by EPA, to demonstrate comp liance with the requirements of this subpart and with the requirements of subparts U and V of this part. These methods are effective for compliance monitoring February 16, 1999, unless a different effective d ate is specified in this section or by the State.

(2) The following documents are incorporated by reference. The Director of the Federal Register approves this incorporation by reference in accordanc e with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be inspected at EPA's Drinking Water Docket, 1301 Constitution Avenue, NW., EPA West, Room B102, Washington, DC 20460, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202–741–6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. EPA Method 552.1 is in Methods for the Determination of Organic Compounds in Drinking Water-Supplement II, USEPA, August 1992, EPA/600/R–92/129 (available through National Information Technical Service (NTIS), PB92–207703). EPA Methods 502.2, 524.2, 551.1, and 552.2 are in Methods for the Determination of Organic Compounds in Drinking Water-Supplement III, USEPA, August 1995, EPA/600/R–95/131 (available through NTIS, PB95–261616). EPA Method 300.0 is in Methods for the Determination of Inorganic Substances in Environmental Samples, USEPA, August 1993, EPA/600/R– 93/100 (available through NTIS, PB94–121811). EPA Methods 300.1 and 321.8 are in Methods for the Determination of Organic and Inorganic Compounds in Drinking Water, Volume 1, USEPA, August 2000, EPA 815–R–00–014 (available through NTIS, PB2000–106981). EPA Method 317.0, Revision 2.0, “Determination of Inorganic Oxyhalide Disinfecti on By-Products in Drinking Water Using Ion Chromatography with the Addition of a Postcolumn Reagent for Trace Bromate Analysis,” USEPA, July 2001, EPA 815–B–01–001, EPA Method 326.0, Revision 1.0, “Determination of Inorganic Oxyhalide Disinfection By-Products in Drin king Water Using Ion Chromatography Incorporating the Addition of a Suppressor Acidified Postcolumn Reagent for Trace Bromate Analysis,” USEPA, June 2002, EPA 815– R–03–007, EPA Method 327.0, Revision 1.1, “Determinati on of Chlorine Dioxide and Chlorite Ion in Drinking Water Using Lissamine Green B and Hors eradish Peroxidase with Detection by Visible Spectrophotometry,” USEPA, May 2005, EPA 815–R–05–008 and EPA Method 552.3, Revision 1.0, “Determination of Haloacetic Acids and Dalapon in Drinking Water by Liquid-liquid Microextraction, Derivatization, and Gas Chromatography with Electron Capture Detection,” USEPA, July 2003, EPA– 815–B–03–002 can be accessed and downloaded directly on-line at 

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...http://www.epa.gov/safewater/m ethods/sourcalt.html. EPA Method 415.3, Revision 1.1, “Determination of Total Organic Carbon and Specific UV Absorbance at 254 nm in Source Water and Drinking Water,” USEPA, February 2005, EPA/600/R–05/055 can be accessed and downloaded directly on-line at www.epa.gov/nerlcwww/ordmeth.htm. Standard Methods 4500–Cl D, 4500–Cl E, 4500–Cl F, 4500–Cl G, 4500–Cl H, 500–Cl I, 4500–ClO 2 D, 4500–ClO 2 E, 6251 B, and 5910 B shall be followed in accordance with Standard Methods for the Examination of Water and Wastewater, 19th or 20th Editions, American Public Health Association, 1995 and 1998, respective ly. The cited methods published in either edition may be used. Standard Methods 5310 B, 5310 C, and 5310 D shall be followed in accordance with the Supplement to the 19th Edition of Standard Methods for the Examination of Water and Wastewater, or the Standard Methods for the Examination of Water and Wastewater, 20th Edition, American Public Health Association, 1996 and 1998, respectively. The ci ted methods published in either edition may be used. Copies may be obtained from the American Publ ic Health Association, 1015 Fifteenth Street, NW., Washington, DC 20005. Standard Methods 4500–Cl D–00, 4500–Cl E–00, 4500–Cl F–00, 4500–Cl G– 00, 4500–Cl H–00, 4500–Cl I–00, 4500–ClO 2 E–00, 6251 B–94, 5310 B–00, 5310 C–00, 5310 D–00 and 5910 B–00 are available at http://www.standardmethods.org or at EPA's Water Docket. The year in which each method was approved by the Standard Methods Committee is designated by the last two digits in the method number. The methods listed are the only Online versions that are IBR-approved. A STM Methods D 1253–86 and D 1253–86 (Reapproved 1996) shall be followed in accordance with the A nnual Book of ASTM Standards, Volume 11.01, American Society for Testing and Materials International, 1996 or any ASTM edition containing the IBR-approved version of the method may be used. ASTM Method D1253–03 shall be followed in accordance with the Annual Book of ASTM Standards, Volume 11.01, American Society for Test ing and Materials International, 2004 or any ASTM edition containing the IBR-approved version of th e method may be used. ASTM Method D 6581–00 shall be followed in accordance with the Annual Book of ASTM Standards, Volume 11.01, American Society for Testing and Materials International, 2001 or an y ASTM edition containing the IBR-approved version of the method may be used; copies may be obtained from the American Society for Testing and Materials International, 100 Barr Harbor Drive, West Conshohocken, PA 19428–2959.
(b) Disinfection byproducts. (1) Systems must measure disinfection byproducts by the methods (as modified by the footnotes) listed in the following table or one of the alternative methods listed in appendix A to subpart C of this part:
Approved Methods for Disinfection Byproduct Compliance Monitoring

1 P&T = purge and trap; GC = gas chromatography; El CD = electrolytic cond uctivity detector; PID = photoionization detector; MS = mass spectrometer; LLE = liquid/liquid extraction; ECD = electron capture detector; SPE = solid phase extraction; IC = ion chromatography; ICP–MS = inductively coupled plasma/mass spectrometer.

2 19th and 20th editions of Standard Methods for the Examination of Water and Wastewater, 1995 and 1998, respectively, American Public Health Associ ation; either of these editions may be used.

3 Annual Book of ASTM Standards, 2001 or any year containing the cited version of the method, Vol 11.01.

4 If TTHMs are the only analytes being measured in the sample, then a PID is not required.

5 The samples must be extracted within 14 days of sample collection.



## Contaminant and methodology 1 

## EPA method Standard method 2 

## SM online 9 

## ASTM method 3 

## TTHM P&T/GC/ElCD & PID 502.2 4 

## P&T/GC/MS 524.2 LLE/GC/ECD 551.1 HAA5 LLE (diazomethane)/GC/ECD 6251 B 5 

## 6251 B– 94 SPE (acidic methanol)/GC/ECD 552.1 5


## LLE (acidic methanol)/GC/ECD 552.2, 552.3 Bromate Ion chromatography 300.1 D 6581– 00 Ion chromatography & post column reaction 317.0 Rev 2.0 6



## , 326.0 6 

## IC/ICP–MS 321.8 6,7 

## Chlorite Amperometric titration 4500– ClO 2 

## E 8 

## 4500– ClO 2 

## E– 00 8 

## Spectrophotometry 327.0 Rev 1.1 8 

## Ion chromatography 300.0, 300.1, 317.0 Rev 2.0, 326.0 D 6581– 00 

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...6 Ion chromatography & post column reaction or IC/IC P-MS must be used for monitoring of bromate for purposes of demonstrating eligibility of reduced monitoring, as prescribed in §141.132(b)(3)(ii).

7 Samples must be preserved at the time of sampling with 50 mg ethylenediamine (EDA)/L of sample and must be analyzed within 28 days.

8 Amperometric titration or spectrophotometry may be used for routine daily monitoring of chlorite at the entrance to the distribution system, as prescribed in §141.132(b)(2)(i)(A). Ion chromatography must be used for routine monthly monitoring of chlorite and addi tional monitoring of chlori te in the distribution system, as prescribed in §141.132(b)(2)(i)(B) and (b)(2)(ii).

9 The Standard Methods Online version that is approved is indicated by the last two digits in the method number which is the year of approval by the Standard Method Committee. Standard Methods Online are available at http://www.standardmethods.org.
(2) Analyses under this section for disinfection byproducts must be conducted by laboratories that have received certification by EPA or the State, except as specified under paragraph (b)(3) of this section. To receive certification to conduct analyses for the DBP contaminants in §§141.64, 141.135, and subparts U and V of this part, the laboratory must:
(i) Analyze Performance Evaluation (PE) samples th at are acceptable to EPA or the State at least once during each consecuti ve 12 month period by each method for which the laboratory desires certification.
(ii) Until March 31, 2007, in these analyses of PE samples, the laboratory must achieve quantitative results within the acceptance limit on a minimum of 80% of the analytes included in each PE sample. The acceptance limit is defined as the 95% confide nce interval calculated around the mean of the PE study between a maximum and minimum acceptance limit of ±50% and ±15% of the study mean.
(iii) Beginning April 1, 2007, the labo ratory must achieve quantitative results on the PE sample analyses that are within the following acceptance limits:

(iv) Beginning April 1, 2007, report quantitative data forconcentrations at least as low as the ones listed in the following table for all DBP samples analyzed for compliance with §§141.64, 141.135, and subparts U and V of this part: 

## DBP Acceptance limits (percent of true value) Comments TTHM Chloroform ±20 Laboratory must meet all 4 individual THM acceptance limits in order to successfully pass a PE sample for TTHM Bromodichloromethane ±20 Dibromochloromethane ±20 Bromoform ±20 HAA5 Monochloroacetic Acid ±40 Laboratory must meet the acceptance limits for 4 out of 5 of the HAA5 compounds in order to successfully pass a PE sample for HAA5 Dichloroacetic Acid ±40 Trichloroacetic Acid ±40 Monobromoacetic Acid ±40 Dibromoacetic Acid ±40 Chlorite ±30 Bromate ±30

DBP Minimum reporting level (mg/L) 1 

## Comments TTHM 2 

## Chloroform 0.0010 Bromodichloromethane 0.0010 Dibromochloromethane 0.0010 Bromoform 0.0010 HAA5 2 

## Monochloroacetic Acid 0.0020 Dichloroacetic Acid 0.0010 Trichloroacetic Acid 0.0010 Monobromoacetic Acid 0.0010 Dibromoacetic Acid 0.0010 

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...1 The calibration curve must encompass the regulatoryminimum reporting le vel (MRL) concentration. Data may be reported for concentrations lower than the regulatory MRL as l ong as the precision and accuracy criteria are met by analyzing an MRL check standard at the lowest reporting limit chosen by the laboratory. The laboratory must verify the accu racy of the calibration curve at the MRL concentration by analyzing an MRL check standard with a concentration less than or equal to 110% of the MRL with each batch of samples. The measured concentration for the MRL check standard must be ±50% of the expected value, if any field sample in the batch has a concentration less than 5 times the regulatory MRL. Method requirements to analyze higher co ncentration check standards and meet tighter acceptance criteria for them must be met in addition to the MRL check standard requirement.

2 When adding the individual trihalomethane or haloac etic acid concentrations to calculate the TTHM or HAA5 concentrations, respectively, a zero is used for any analytical result that is less than the MRL concentration for that DBP, unless otherwise specified by the State.
(3) A party approved by EPA or the State must measure daily chlorite samples at the entrance to the distribution system.
(c) Disinfectant residuals. (1) Systems must measure residual disinfectant concentration for free chlorine, combined chlorine (chloramines), and chlorine dioxide by the methods listed in the following table or one of the alternative methods listed in appendix A to subpart C of this part:

1 X indicates method is approved for measuring spec ified disinfectant residual. Free chlorine or total chlorine may be measured for demonstrating compliance with the chlorine MRDL and combined chlorine, or total chlorine may be measured for demonstrating compliance with the chloramine MRDL.

2 The Standard Methods Online version that is approved is indicated by the last two digits in the method number which is the year of approval by the Standard Method Committee. Standard Methods Online are available at http://www.standardmethods.org.

(2) If approved by the State, systems may also measure residual disinfectant concentrations for chlorine, chloramines, and chlorine dioxide by using DPD colorimetric test kits.
(3) A party approved by EPA or the State mustmeasure residual disinfectant concentration.
(d) Additional analytical methods. Systems required to analyze parameters not included in paragraphs (b) and (c) of this section must use the following methods or one of the alternative methods listed in appendix A to subpart C of this part. A party app roved by EPA or the State must measure these parameters.
(1) Alkalinity. All methods allowed in §141.89(a) for measuring alkalinity. 

## Chlorite 0.020 Applicable to monitoring as prescribed in §141.132(b)(2) (1)(B) and (b)(2)(ii). Bromate 0.0050 or 0.0010 Laboratories that use EPA Methods 317.0 Revision 2.0, 326.0 or 321.8 must meet a 0.0010 mg/L MRL for bromate.

Methodology SM (19th

or 20th ed) SM Online 2 

## ASTM method EPA method Residual measured 1



## Free Cl 2 

## Combined Cl 2 

## Total Cl 2 

## ClO 2 

## Amperometric Titration 4500– Cl D 4500– Cl D– 00 D 1253– 86 (96), 03 XX X

Low Level Amperometric Titration 4500– Cl E 4500– Cl E–00 X

DPD Ferrous Titrimetric 4500– Cl F 4500– Cl F–00 XX X

DPD Colorimetric 4500– Cl G 4500– Cl G– 00 XX X

Syringaldazine (FACTS) 4500– Cl H 4500– Cl H– 00 X

Iodometric Electrode 4500– Cl I 4500– Cl I–00 X

DPD 4500– ClO 2 

## D X

Amperometric Method II 4500– ClO 2 

## E 4500– ClO 2 

## E– 00 X

Lissamine Green Spectrophotometric 327.0 Rev 1.1 X 

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...(2) Bromide. EPA Methods 300.0, 300.1, 317.0 Revision 2.0, 326.0, or ASTM D 6581–00.
(3) Total Organic Carbon (TOC). Standard Method 5310 B or 5310 B–00 (High-TemperatureCombustion Method) or Standard Method 5310 C or 5310 C–00 (Persulfate-Ultraviolet or HeatedPersulfate Oxidation Method) or Standard Method 5310 D or 5310 D–00 (Wet-Oxidation Method) or EPA Method 415.3 Revision 1.1. Inorganic carbon must be removed from the samples prior to analysis. TOC samples may not be filtered prior to analysis. TOC samples must be acidified at the time of sample collection to achieve pH less than or equal to 2 with minimal addition of the acid specified in the method or by the instrument manufacturer. Acidified TOC samples must be analyzed within 28 days.

(4) Specific Ultraviolet Absorbance (SUVA). SUVA is equal to the UV absorption at 254nm (UV 254 ) (measured in m- 1 divided by the dissolved organic carbon (DOC) concentration (measured as mg/L). In order to determine SUVA, it is necessary to separately measure UV 254 and DOC. When determining SUVA, systems must use the methods stipulated in paragraph (d)(4)(i) of this section to measure DOC and the method stipulated in paragraph (d )(4)(ii) of this section to measure UV 254 . SUVA must be determined on water prior to the addition of disi nfectants/oxidants by the system. DOC and UV 254 samples used to determine a SUVA value must be taken at the same time and at the same location.
(i) Dissolved Organic Carbon (DOC). Standard Method 5310 B or 5310 B–00 (High-TemperatureCombustion Method) or Standard Method 5310 C or 5310 C–00 (Persulfate-Ultraviolet or HeatedPersulfate Oxidation Method) or Standard Method 5310 D or 5310 D–00 (Wet-Oxidation Method) or EPA Method 415.3 Revision 1.1. DOC samples must be filtered through the 0.45 μ m pore-diameter filter as soon as practical after sampling, not to exceed 48 hours. After filtration, DOC samples must be acidified to achieve pH less than or equal to 2 with minimal add ition of the acid specified in the method or by the instrument manufacturer. Acidified DOC samples must be analyzed within 28 days of sample collection. Inorganic carbon must be removed from the sample s prior to analysis. Water passed through the filter prior to filtration of the sample must serve as the fi ltered blank. This filtered blank must be analyzed using procedures identical to those used for analysis of the samples and must meet the following criteria: DOC < 0.5 mg/L.
(ii) Ultraviolet Absorption at 254 nm (UV 254 ). Standard Method 5910 B or 5910 B–00 (Ultraviolet A bsorption Method) or EPA Method 415.3 Revision 1.1. UV absorption must be measured at 253.7 nm (may be rounded off to 254 nm). Prior to analysis, UV 254 samples must be filtered through a 0.45 μ m pore-diameter filter. The pH of UV 254 samples may not be adjusted. Samples must be analyzed as soon as practical after sampling, not to exceed 48 hours.

(5) pH. All methods allowed in §141.23(k)(1) for measuring pH.
(6) Magnesium. All methods allowed in §141.23(k)(1) for measuring magnesium.

[63 FR 69466, Dec. 16, 1998, as amended at 66 FR 3776, Jan. 16, 2001; 71 FR 479, Jan. 4, 2006; 71 FR 37168, June 29, 2006; 74 FR 30958, June 29, 2009]


### § 141.132 Monitoring requirements.

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(a) General requirements. (1) Systems must take all samples du ring normal operating conditions.
(2) Systems may consider multiple wells drawing wate r from a single aquifer as one treatment plant for determining the minimum number of TTHM and HAA5 samples required, with State approval in accordance with criteria developed under §142.16(h)(5) of this chapter.
(3) Failure to monitor in accordance with the monitor ing plan required under paragraph (f) of this section is a monitoring violation.
(4) Failure to monitor will be treated as a violation for the entire period covered by the annual average where compliance is based on a running annual avera ge of monthly or quarterly samples or averages and the system's failure to monitor makes it impossible to determine compliance with MCLs or MRDLs.
(5) Systems may use only data collected under the provisions of this subpart to qualify for reduced monitoring.
(b) Monitoring requirements for disinfection byproducts —(1) TTHMs and HAA5 —(i) Routine monitoring. Systems must monitor at the frequency indicated in the following table:

Routine Monitoring Frequency for TTHM and HAA5



## Type of system Minimum monitoring frequency Sample location in the distribution system Subpart H system serving at least 10,000 persons Four water samples per quarter per treatment plant At least 25 percent of all samples collected each quarter at locations representing maximum residence time. Remaining samples taken at locations representative of at least average residence time in the distribution system and representing the entire distribution system, taking into account number of persons served, different sources of water, and different treatment methods. 1 

## Subpart H system serving from 500 to One water sample per Locations representing maximum residence time. 1 

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...1 If a system elects to sample more frequently than the minimum required, at least 25 percent of all samples collected each quarter (inc luding those taken in excess of the required frequency) must be taken at locations that represent the maximum residenc e time of the water in the distribution system. The remaining samples must be taken at locations re presentative of at least av erage residence time in the distribution system.

2 Multiple wells drawing water from a single aquifer may be considered one treatment plant for determining the minimum number of samples required, with State approval in accordance with criteria developed under §142.16(h)(5) of this chapter.
(ii) Systems may reduce monitoring, except as otherwise provided, in accordance with the following table:
Reduced Monitoring Frequency for TTHM and HAA5 

## 9,999 persons quarter per treatment plant Subpart H system serving fewer than 500 persons One sample per year per treatment plant during month of warmest water temperature. Locations representing maximum residence time. 1 

## If the sample (or average of annual samples, if more than one sample is taken) exceeds the MCL, the system must increase monitoring to one sample per treatment plant per quarter, taken at a point reflecting the maximum residence time in the distribution system, until the system meets criteria in paragraph (b)(1)(iv) of this section. System using only ground water not under direct influence of surface water using chemical disinfectant and serving at least 10,000 persons One water sample per quarter per treatment plant 2 

## Locations representing maximum residence time. 1



## System using only ground water not under direct influence of surface water using chemical disinfectant and serving fewer than 10,000 persons One sample per year per treatment plant 2 

## during month of warmest water temperature. Locations representing maximum residence time. 1 

## If the sample (or average of annual samples, if more than one sample is taken) exceeds the MCL, the system must increase monitoring to one sample per treatment plant per quarter, taken at a point reflecting the maximum residence time in the distribution system, until the system meets criteria in paragraph (b)(1)(iv) of this section.

If you are a . . . You may reduce monitoring if you have monitored at least one

year and your . . . To this level Subpart H system serving at least 10,000 persons which has a source water annual average TOC level, before any treatment, ≤ 4.0 mg/L TTHM annual average ≤ 0.040 mg/L and HAA5 annual average ≤ 0.030 mg/L One sample per treatment plant per quarter at distribution system location reflecting maximum residence time.

Subpart H system serving from 500 to 9,999 persons which has a source water annual average TOC level, before any treatment, ≤ 4.0 mg/L TTHM annual average ≤ 0.040 mg/L and HAA5 annual average ≤ 0.030 mg/L One sample per treatment plant per year at distribution system location reflecting maximum residence time during month of warmest water temperature. NOTE: Any Subpart H system serving fewer than 500 persons may not reduce its monitoring to less than one sample per treatment plant per year. System using only ground water not under direct influence of surface TTHM annual average ≤ 0.040 mg/L and HAA5 annual average ≤ 0.030 mg/L One sample per treatment plant per year at distribution system location reflecting maximum residence time during month of 

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...(iii) Monitoring requirements for source water TOC. In order to qualify for reduced monitoring for TTHM and HAA5 under paragraph (b)(1)(ii) of this section, subpart H systems not monitoring under the provisions of paragraph (d) of this section must take monthly TOC samples every 30 days at a location prior to any treatment, beginning April 1, 2008 or earlie r, if specified by the State. In addition to meeting other criteria for reduced monitoring in paragraph (b)( 1)(ii) of this section, the source water TOC running annual average must be ≤ 4.0 mg/L (based on the most recent four quarters of monitoring) on a continuing basis at each treatment plant to reduce or remain on reduced monitoring for TTHM and HAA5. Once qualified for reduced monitoring for TTHM and HAA5 under paragraph (b)(1)(ii) of this section, a system may reduce source water TOC m onitoring to quarterly TOC samples taken every 90 days at a location prior to any treatment.
(iv) Systems on a reduced monitoring schedule may re main on that reduced schedule as long as the average of all samples taken in the year (for systems wh ich must monitor quarterly) or the result of the sample (for systems which must monitor no more frequently than annually) is no more than 0.060 mg/L and 0.045 mg/L for TTHMs and HAA5, respectively. Sys tems that do not meet these levels must resume monitoring at the frequency identified in paragraph (b)(1)(i) of this section (minimum monitoring frequency column) in the quarter immediately following the monitoring period in which the system exceeds 0.060 mg/L or 0.045 mg/L for TTHMs and HAA 5, respectively. For systems using only ground water not under the direct influence of surface water and serving fewer than 10,000 persons, if either the TTHM annual average is >0.080 mg/L or the HAA5 annual average is >0.060 mg/L, the system must go to the increased monitoring identified in paragraph (b)(1) (i) of this section (sample location column) in the quarter immediately following the monitoring period in which the system exceeds 0.080 mg/L or 0.060 mg/L for TTHMs or HAA5 respectively.

(v) Systems on increased monitoring may return to ro utine monitoring if, after at least one year of monitoring their TTHM annual average is ≤ 0.060 mg/L and their HAA5 annual average is ≤ 0.045 mg/L.
(vi) The State may return a system to routine monitoring at the State's discretion.
(2) Chlorite. Community and nontransient noncommunity water systems using chlorine dioxide, for disinfection or oxidation, must c onduct monitoring for chlorite.
(i) Routine monitoring. (A) Daily monitoring. Systems must take daily samples at the entrance to the distribution system. For any daily sample that exceeds the chlorite MCL, the system must take additional samples in the distribution system the following day at the locations required by paragraph (b)(2)(ii) of this section, in addition to the sample required at the entrance to the distribution system.
(B) Monthly monitoring. Systems must take a three-sample set each month in the distribution system. The system must take one sample at each of the following locations: near the first customer, at a location representative of average re sidence time, and at a location refl ecting maximum residence time in the distribution system. Any ad ditional routine sampling must be conducted in the same manner (as three-sample sets, at the specified locations). The system may use the results of additional monitoring conducted under paragraph (b)(2)(ii) of this section to meet the requirement for monitoring in this paragraph.
(ii) Additional monitoring. On each day following a routine sample monitoring result that exceeds the chlorite MCL at the entrance to the distribution syste m, the system is require d to take three chlorite distribution system samples at the following locations: as close to the first customer as possible, in a location representative of average re sidence time, and as close to the end of the distribution system as possible (reflecting maximum residence time in the distribution system).
(iii) Reduced monitoring. (A) Chlorite monitoring at the entrance to the distribution system required by paragraph (b)(2)(i)(A) of this section may not be reduced.

(B) Chlorite monitoring in the distribution system requ ired by paragraph (b)(2)(i)(B) of this section may be reduced to one three-sample set per quarter after one year of monitoring where no individual chlorite sample taken in the distribution system under paragr aph (b)(2)(i)(B) of this section has exceeded the chlorite MCL and the system has not been required to conduct monitoring under paragraph (b)(2)(ii) of this section. The system may remain on the reduced monitoring schedule until either any of the three individual chlorite samples taken quarterly in the dist ribution system under paragraph (b)(2)(i)(B) of this section exceeds the chlorite MCL or the system is required to conduct monitoring under paragraph (b)(2) (ii) of this section, at which time the sy stem must revert to routine monitoring.
(3) Bromate —(i) Routine monitoring. Community and nontransient nonco mmunity systems using ozone, for disinfection or oxidation, musttake one sample per month for each treatment plant in the system using ozone. Systems must take samples monthly at the entrance to the distribution system while the ozonation system is operating under normal conditions.
(ii) Reduced monitoring. (A) Until March 31, 2009, systems required to analyze for bromate may reduce monitoring from monthly to quarterly, if the system's average source water bromide concentration is less than 0.05 mg/L based on representative monthly bromi de measurements for one year. The system may remain on reduced bromate monitoring until the running annual average source water bromide concentration, computed quarterly, is equal to or greater than 0.05 mg/L based on representative monthly measurements. If the running annual average source water bromide concentration is ≥ 0.05 mg/L, the system must resume routine monitoring required by paragraph (b)(3)(i) of this section in the following month. 

## water using chemical disinfectant and serving at least 10,000 persons warmest water temperature

System using only ground water not under direct influence of surface water using chemical disinfectant and serving fewer than 10,000 persons TTHM annual average ≤ 0.040 mg/L and HAA5 annual average ≤ 0.030 mg/L for two consecutive years OR TTHM annual average ≤ 0.020 mg/L and HAA5 annual average ≤ 0.015 mg/L for one year One sample per treatment plant per three year monitoring cycle at distribution system location reflecting maximum residence time during month of warmest water temperature, with the three-year cycle beginning on January 1 following quarter in which system qualifies for reduced monitoring. 

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...(B) Beginning April 1, 2009, systems may no longer use the provisions of paragraph (b)(3)(ii)(A) of this section to qualify for reduced monitoring. A system required to analyze for bromate may reduce monitoring from monthly to quarterly, if the system 's running annual average bromate concentration is ≤ 0.0025 mg/L based on monthly bromate measurements under paragraph (b)(3)(i) of this section for the most recent four quarters, with samples analyzed using Method 317.0 Revision 2.0, 326.0 or 321.8. If a system has qualified for reduced bromate monitoring under paragraph (b)(3)(ii)(A) of this section, that system may remain on reduced m onitoring as long as the running annual average of quarterly bromate samples ≤ 0.0025 mg/L based on samples analyzed using Method 317.0 Revision 2.0, 326.0, or 321.8. If the running annual average bromate concentration is >0.0025 mg/L, the system must resume routine monitoring required by paragraph (b)(3)(i) of this section.
(c) Monitoring requirements for disinfectant residuals —(1) Chlorine and chloramines —(i) Routine monitoring. Community and nontransient noncommunity water systems that use chlorine or chloramines must measure the residual disinfectant level in the distribution system at the same point in the distribution system and at the same time as total coliforms are sampled, as specified in §141.21. Subpart H systems may use the results of residual disinfectant concentration sa mpling conducted under §141.74(b)(6)(i) for unfiltered systems or §141.74(c)(3 )(i) for systems which filter, in lieu of taking separate samples.
(ii) Reduced monitoring. Monitoring may not be reduced.
(2) Chlorine dioxide —(i) Routine monitoring. Community, nontransient noncom munity, and transient noncommunity water systems that use chlorine diox ide for disinfection or ox idation must take daily samples at the entrance to the distribution system. For any daily sample that exceeds the MRDL, the system must take samples in the distribution system the following day at the locations required by paragraph (c)(2)(ii) of this section, in addition to the sample required at the entrance to the distribution system.
(ii) Additional monitoring. On each day following a routine sample monitoring result that exceeds the MRDL, the system is required to take three chlorine dioxide distribution system samples. If chlorine dioxide or chloramines are used to maintain a disinfectant residual in the distribution system, or if chlorine is used to maintain a disinfectant residual in the distribution system and there are no disinfection addition points after the entrance to the distribution system ( i.e. , no booster chlorination), the system must take three samples as close to the first customer as possible, at intervals of at least six hours. If chlorine is used to maintain a disinfectant residual in the distribution system and there are one or more disinfection addition points after the entrance to the distribution system ( i.e. , booster chlorination), the system must take one sample at each of the followin g locations: as close to the first customer as possible, in a location representative of average residence time, and as close to the end of the distribution system as possible (r eflecting maximum residence time in the distribution system).
(iii) Reduced monitoring. Chlorine dioxide monitoring may not be reduced.
(d) Monitoring requirements for disinfect ion byproduct precursors (DBPP) —(1) Routine monitoring. Subpart H systems which use conventional filtration treatment (as defined in §141.2) must monitor each treatment plant for TOC no later than the point of combined filter effluent turbidity monitoring and representative of the treated water. All systems required to monitor under this paragraph (d)(1) must also monitor for TOC in the source water prior to any treatment at the same time as monitoring for TOC in the treated water. These samples (source water and treated water) are referred to as paired samples. At the same time as the source water sample is tak en, all systems must monitor for alkalinity in the source water prior to any treatment. Systems must take one paired sample and one source water alkalinity sample per month per plant at a time repres entative of normal operating conditions and influent water quality.
(2) Reduced monitoring. Subpart H systems with an average treated water TOC of less than 2.0 mg/L for two consecutive years, or less than 1.0 mg/L fo r one year, may reduce monitoring for both TOC and alkalinity to one paired sample and one source water alkalinity sample per plant per quarter. The system must revert to routine monitoring in the month fol lowing the quarter when the annual average treated water TOC ≥ 2.0 mg/L.
(e) Bromide. Systems required to analyze for bromate may reduce bromate monitoring from monthly to once per quarter, if the system demonstrates that the average source water bromide concentration is less than 0.05 mg/L based upon representative monthly measurements for one year. The system must continue bromide monitoring to remain on reduced bromate monitoring.
(f) Monitoring plans. Each system required to monitor under this subpart must develop and implement a monitoring plan. The system must ma intain the plan and make it avail able for inspection by the State and the general public no later than 30 days follo wing the applicable compliance dates in §141.130(b). A ll Subpart H systems serving more than 3300 people mu st submit a copy of the monitoring plan to the State no later than the date of the first report required under §141.134. The State may also require the plan to be submitted by any other system. After re view, the State may require changes in any plan elements. The plan must include at least the following elements.
(1) Specific locations and schedules for collecting sa mples for any parameters included in this subpart.
(2) How the system will calculate compliance with MCLs, MRDLs, and treatment techniques.
(3) If approved for monitoring as a consecutive system, or if provid ing water to a consecutive system, under the provisions of §141.29, the sampling plan must reflect the entire distribution system.

[63 FR 69466, Dec. 16, 1998, as amended at 66 FR 3776, Jan. 16, 2001; 69 FR 38856, June 29, 2004; 71 FR 482, Jan. 4, 2006]


### § 141.133 Compliance requirements.

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(a) General requirements. (1) Where compliance is based on a running annual average of monthly or quarterly samples or averages and the system fails to monitor for TTHM, HAA5, or bromate, this failure to monitor will be treated as a monitoring violation fo r the entire period covered by the annual average. Where compliance is based on a running annual average of monthly or quarterly samples or averages and the system failure to monitor makes it impo ssible to determine compliance with MRDLs for chlorine and chloramines, this failure to monitor will be treate d as a monitoring violati on for the entire period covered by the annual average.
(2) All samples taken and analyzed under the provisions of this subpart must be included in determining 

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...compliance, even if that number is greater than the minimum required.
(3) If, during the first year of monitoring under §141.13 2, any individual quarter's average will cause the running annual average of that system to exceed the MCL for total trihalomethan es, haloacetic acids (five), or bromate; or the MRDL for chlorine or chloramine, the system is out of compliance at the end of that quarter.
(b) Disinfection byproducts —(1) TTHMs and HAA5. (i) For systems monitori ng quarterly, compliance with MCLs in §141.64 must be based on a running ann ual arithmetic average, computed quarterly, of quarterly arithmetic averages of all samples collected by the system as prescribed by §141.132(b)(1).
(ii) For systems monitoring less frequently than quarter ly, systems demonstrate MCL compliance if the average of samples taken that year under the provis ions of §141.132(b)(1) does not exceed the MCLs in §141.64. If the average of these samples exceeds the MCL, the system must increase monitoring to once per quarter per treatment plant and such a sys tem is not in violation of the MCL until it has completed one year of quarterly monitoring, unless th e result of fewer than four quarters of monitoring will cause the running an nual average to exceed the MCL, in which case the system is in violation at the end of that quarter. Systems required to increase monitoring frequency to quarterly monitoring must calculate compliance by including the sample whic h triggered the increased monitoring plus the following three quarters of monitoring.
(iii) If the running annual arithmetic average of quarte rly averages covering an y consecutive four-quarter period exceeds the MCL, the system is in violation of the MCL and must notify the public pursuant to §141.32 or §141.202, whichever is effective for yoursystem, in addition to reporting to the State pursuant to §141.134.
(iv) If a PWS fails to complete four consecutive quarters of monitoring, compliance with the MCL for the last four-quarter compliance period must be based on an average of the available data.
(2) Bromate. Compliance must be based on a running an nual arithmetic average, computed quarterly, of monthly samples (or, for months in which the syste m takes more than one sample, the average f all samples taken during the month) collected by the system as prescribed by §141.132(b)(3). If the average of samples covering any consecutive four-quarter period exceeds the MCL, the system is in violation of the MCL and must notify the public purs uant to subpart Q, in addition to reporting to the State pursuant to §141.134. If a PWS fails to complete 12 consecutive months' moni toring, compliance with the MCL for the last four-quarter compliance period must be based on an average of the available data.
(3) Chlorite. Compliance must be based on an arithmetic average of each three sample set taken in the distribution system as prescribed by §141.132(b)(2) (i)(B) and §141.132(b)(2)(ii). If the arithmetic average of any three sample set exceeds the MCL, the system is in violation of the MCL and must notify the public pursuant to subpart Q, in addition to reporting to the State pursuant to §141.134.
(c) Disinfectant residuals —(1) Chlorine and chloramines. (i) Compliance must be based on a running annual arithmetic average, computed quarterly, of monthly averages of all samples collected by the system under §141.132(c)(1). If the average covering any consecutive four-quarter period exceeds the MRDL, the system is in violation of the MRDL and mu st notify the public pursuant to subpart Q, in addition to reporting to the State pursuant to §141.134.
(ii) In cases where systems switch between the use of chlorine and chloramines for residual disinfection during the year, compliance must be determined by including together all monitoring results of both chlorine and chloramines in calculating complianc e. Reports submitted pursuant to §141.134 must clearly indicate which residual disi nfectant was analyzed for each sample.
(2) Chlorine dioxide. (i) Acute violations. Compliance must be based on consecutive daily samples collected by the system under §141.132(c)(2). If any daily sample taken at the entrance to the distribution system exceeds the MRDL, and on the following day one (or more) of the three samples taken in the distribution system exceed the MRDL, the system is in violation of the MRDL and must take immediate corrective action to lower the level of chlo rine dioxide below the MRDL and must notify the public pursuant to the procedures for acute health risks in subpart Q in addition to reporting to the State pursuant to §141.134. Failure to take samples in the distribution system the day following an exceedance of the chlorine dioxide MRDL at the entrance to the distribution system will also be considered an MRDL violation and the system must noti fy the public of the violation in accordance with the provisions for acute violations under subpart Q in addition to reporting to the State pursuant to §141.134.
(ii) Nonacute violations. Compliance must be based on consec utive daily samples collected by the system under §141.132(c)(2). If any two consecutive daily sample s taken at the entrance to the distribution system exceed the MRDL and all di stribution system samples taken are below the MRDL, the system is in violation of the MRDL and must tak e corrective action to lower the level of chlorine dioxide below the MRDL at the point of sampling and will notify the public pursuant to the procedures for nonacute health risks in subpart Q in addition to reporting to the State pursuant to §141.134. Failure to monitor at the entrance to the distribution system the day following an exceedance of the chlorine dioxide MRDL at the entrance to the distribution system is also an MRDL violation and the system must notify the public of the violation in accordance wi th the provisions for nonacute violations under §141.32 (e)(78) in addition to reporting to the State pursuant to §141.134.
(d) Disinfection byproduct precursors (DBPP). Compliance must be determined as specified by §141.135(c). Systems may begin monitoring to determine whether Step 1 TOC removals can be met 12 months prior to the compliance date for the system. This monitoring is not required and failure to monitor during this period is not a violation. However, any system that does not monitor during this period, and then determines in the first 12 months after the compliance date that it is not able to meet the Step 1 requirements in §141.135(b)(2) and must therefore apply for alternate minimum TOC removal (Step 2) requirements, is not eligible for retroactive ap proval of alternate minimum TOC removal (Step 2) requirements as allowed pursuant to §141.135(b)(3) a nd is in violation. Systems may apply for alternate minimum TOC removal (Step 2) requirements any time after the compliance date. For systems required to meet Step 1 TOC removals, if the value calculated under §141.135(c)(1)(iv) is less than 1.00, the system is in violation of the trea tment technique requirements and mu st notify the public pursuant to subpart Q of this part, in addition to reporting to the State pursuant to §141.134.

[63 FR 69466, Dec. 16, 1998, as amended at 65 FR 26022, May 4, 2000; 65 FR 40521, June 30, 2000; 66 FR 3777, Jan. 16, 2001; 69 FR 38856, June 29, 2004; 71 FR 482, Jan. 4, 2006]


### § 141.134 Reporting and recordkeeping requirements.

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...(a) Systems required to sample quarterly or more frequently must report to the State within 10 days after the end of each quarter in which samples were collected, notwithstanding the provisions of §141.31. Systems required to sample less frequently than quarterly must report to the State within 10 days after the end of each monitoring period in which samples were collected.

(b) Disinfection byproducts. Systems must report the information specified in the following table:

1 The State may choose to perform calculations and determine whether the MCL was exceeded, in lieu of having the system report that information

(c) Disinfectants. Systems must report the information specified in the following table: 

## If you are a * * * You must report * * * (1) System monitoring for TTHMs and HAA5 under the requirements of §141.132(b) on a quarterly or more frequent basis. (i) The number of samples taken during the last quarter. (ii) The location, date, and result of each sample taken during the last quarter. (iii) The arithmetic average of all samples taken in the last quarter. (iv) The annual arithmetic average of the quarterly arithmetic averages of this section for the last four quarters. (v) Whether, based on §141.133(b) (1), the MCL was violated. (2) System monitoring for TTHMs and HAA5 under the requirements of §141.132(b) less frequently than quarterly (but as least annually). (i) The number of samples taken during the last year. (ii) The location, date, and result of each sample taken during the last monitoring period. (iii) The arithmetic average of all samples taken over the last year. (iv) Whether, based on §141.133(b) (1), the MCL was violated. (3) System monitoring for TTHMs and HAA5 under the requriements of §141.132(b) less frequently than annually. (i) The location, date, and result of each sample taken (ii) Whether, based on §141.133(b)(1), the MCL was violated. (4) System monitoring for chlorite under the requirements of §141.132 (b) (i) The number of entry point samples taken each month for the last 3 months. (ii) The location, date, and result of each sample (both entry point and distribution system) taken during the last quarter. (iii) For each month in the reporting period, the arithmetic average of all samples taken in each three samples set taken in the distribution system. (iv) Whether, based on §141.133(b) (3), the MCL was violated, in which month, and how many times it was violated each month. (5) System monitoring for bromate under the requirements of §141.132 (b). (i)The number of samples taken during the last quarter. (ii)The location, date, and result of each sample taken during the last quarter. (iii) The arithmetic average of the monthly arithmetic averages of all samples taken in the last year. (iv) Whether, based on §141.133(b) (2), the MCL was violated.

If you are a * * * You must report * * * (1) System monitoring for chlorine or chloramines under the requirements of §141.132(c) (i) The number of samples taken during each month of the last quarter. (ii) The month arithmetic average of all samples taken in each month for the last 12 months. (iii) The arithmetic average of the monthly averages for the last 12 months. (iv) Whether, based on §141.133(c)(1), the MRD was violated. (2) System monitoring for chlorine dioxide under the (i) The dates, result, and locations of samples taken during the last quarter. 

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...1 The State may choose to perform calculations and dete rmine whether the MRDL was exceeded, in lieu of having the system report that information.
(d) Disinfection byproduct precursors a nd enhanced coagulation or enhanced softening. Systems must report the information specified in the following table: 

## requirements of §141.132(c). (ii) Whether, based on §141.133(c)(2), the MRDL was violated. (iii) Whether the MRDL was exceeded in any two consecutive daily samples and whether the resulting violation was acuate or nonacute.

If you are a... You must report... 1 

## (1) System monitoring monthly or quarterly for TOC under the requirements of §141.132(d) and required to meet the enhanced coagulation or enhanced softening requirements in §141.135(b)(2) or (3) (i) The number of paired (source water and treated water) samples taken during the last quarter. (ii) The location, date, and results of each paired sample and associated alkalinity taken during the last quarter. (iii) For each month in the reporting period that paired samples were taken, the arithmetic average of the percent reduction of TOC for each paired sample and the required TOC percent removal. (iv) Calculations for determining compliance with the TOC percent removal requirements, as provided in §141.135(c)(1). (v) Whether the system is in compliance with the enhanced coagulation or enhanced softening percent removal requirements in §141.135(b) for the last four quarters. (2) System monitoring monthly or quarterly for TOC under the requirements of §141.132(d) and meeting one or more of the alternative compliance criteria in §141.135(a)(2) or (3) (i) The alternative compliance criterion that the system is using.

(ii) The number of paired samples taken during the last quarter. (iii) The location, date, and result of each paired sample and associated alkalinity taken during the last quarter. (iv) The running annual arithmetic average based on monthly averages (or quarterly samples) of source water TOC for systems meeting a criterion in §§141.135(a)(2)(i) or (iii) or of treated water TOC for systems meeting the criterion in §141.135(a)(2)(ii). (v) The running annual arithmetic average based on monthly averages (or quarterly samples) of source water SUVA for systems meeting the criterion in §141.135(a)(2)(v) or of treated water SUVA for systems meeting the criterion in §141.135(a)(2)(vi). (vi) The running annual average of source water alkalinity for systems meeting the criterion in §141.135(a)(2)(iii) and of treated water alkalinity for systems meeting the criterion in §141.135(a)(3)(i). (vii) The running annual average for both TTHM and HAA5 for systems meeting the criterion in §141.135(a)(2)(iii) or (iv). (viii) The running annual average of the amount of magnesium hardness removal (as CaCO 3 

## , in mg/L) for systems meeting the criterion in §141.135(a)(3)(ii). (ix) Whether the system is in compliance with the particular alternative compliance criterion in §141.135(a)(2) or (3). 

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...1 The State may choose to perform calculations an d determine whether the treatment technique was met, in lieu of having the system report that information.

[63 FR 69466, Dec. 16, 1998, as amended at 66 FR 3778, Jan. 16, 2001; 66 FR 9903, Feb. 12, 2001]


### § 141.135 Treatment technique for control of disinfection byproduct (DBP) precursors.

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(a) Applicability. (1) Subpart H systems using conventional filt ration treatment (as defined in §141.2 ) must operate with enhanced coagulation or enhanc ed softening to achieve the TOC percent removal levels specified in paragraph (b) of this section unless the system meets at leas t one of the alternative compliance criteria listed in paragraph (a)(2) or (a)(3) of this section.
(2) Alternative compliance criteria for enhanc ed coagulation and enhanced softening systems. Subpart H systems using conventional filtration treatmen t may use the alternative compliance criteria in paragraphs (a)(2)(i) through (vi) of this section to comply with this section in lieu of complying with paragraph (b) of this section. Systems must still comply with monitoring requ irements in §141.132(d).
(i) The system's source water TOC level, measured according to §141.131(d)(3), is less than 2.0 mg/L, calculated quarterly as a running annual average.
(ii) The system's treated water TOC level, measured according to §141.131(d)(3), is less than 2.0 mg/L, calculated quarterly as a running annual average.
(iii) The system's source water TOC level, measur ed according to §141.131(d)(3), is less than 4.0 mg/L, calculated quarterly as a running annual average; the source water alkalinity , measured according to §141.131(d)(1), is greater than 60 mg/L (as CaCO 3 ), calculated quarterly as a running annual average; and either the TTHM and HAA5 running annual averages are no greater than 0.040 mg/L and 0.030 mg/L, respectively; or prior to the effective date for compliance in §141.130(b), the system has made a clear and irrevocable financial commitment not later than the effective date for compliance in §141.130 (b) to use of technologies that will limit the levels of TTHMs and HAA5 to no more than 0.040 mg/L and 0.030 mg/L, respectively. Systems must submit ev idence of a clear and irrevocable financial commitment, in addition to a schedule containing milestones and periodic progress reports for installation and operation of appropriate technolog ies, to the State for approval not later than the effective date for compliance in §141.130(b). These technologies must be installed and operating not later than June 30, 2005. Failure to install and operate these technologies by the date in the approved schedule will constitute a violation of National Primary Drinking Water Regulations.

(iv) The TTHM and HAA5 running annual averages are no greater than 0.040 mg/L and 0.030 mg/L, respectively, and the system uses only chlorine for primary disinfecti on and maintenance of a residual in the distribution system.
(v) The system's source water SUVA, prior to any treatment and measured monthly according to §141.131(d)(4), is less than or equal to 2.0 L/mg-m, calculated quarterly as a running annual average.
(vi) The system's finished water SUVA, measured monthly according to §141.131(d)(4), is less than or equal to 2.0 L/mg-m, calculated quarterly as a running annual average.
(3) Additional alternative compliancecriteria for softening systems. Systems practicing enhanced softening that cannot achieve the TOC removals requi red by paragraph (b)(2) of this section may use the alternative compliance criteria in paragraphs (a)(3)(i) and (ii) of this section in lieu of complying with paragraph (b) of this section. Systems must still comply with monitoring requ irements in §141.132(d).
(i) Softening that results in lowering the treated water alkalinity to less than 60 mg/L (as CaCO 3 ), measured monthly according to §141.131(d)(1) and ca lculated quarterly as a running annual average.
(ii) Softening that results in removing at least 10 mg/L of magnesium hardness (as CaCO 3 ), measured monthly according to §141.131(d)(6) and calculat ed quarterly as a running annual average.
(b) Enhanced coagulation and enhanced so ftening performance requirements. (1) Systems must achieve the percent reduction of TOC specified in paragraph (b)(2) of this section between the source water and the combined filter effluent, unless the State approves a system's request for alternate minimum TOC removal (Step 2) requirements under paragraph (b)(3) of this section.
(2) Required Step 1 TOC reductions, indicated in the following table, are based upon specified source water parameters measured in accordance with § 141.131(d). Systems practicing softening are required to meet the Step 1 TOC reductions in the far-right column (Source water alkalinity >120 mg/L) for the specified source water TOC:
Step 1 Required Removal of TOC by Enhanced Coagulation and Enhanced Softening for Subpart H Systems Using Conventional Treatment 1,2

1 Systems meeting at least one of the conditions in paragraph (a)(2)(i)–(vi) of this section are not required to operate with enhanced coagulation.

2 Softening system meeting one of the alternative compli ance criteria in paragraph (a)(3) of this section are not required to operate with enhanced softening.

3 System practicing softening must meet the TOC removal requirements in this column. 

## Source-water

TOC, mg/L Source-water alkalinity, mg/L as CaCO 3 

## (in precentages)
0–60 >60–120 >120 3 

## >2.0–4.0 35.0 25.0 15.0 >4.0–8.0 45.0 35.0 25.0 >8.0. 50.0 40.0 30.0 

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...(3) Subpart H conventional treatment systems that cannot achieve the Step 1 TOC removals required by paragraph (b)(2) of this section due to water quality parameters or operational constraints must apply to the State, within three months of fa ilure to achieve the TOC removals required by paragraph (b)(2) of this section, for approval of alternative minimum TOC (Step 2) removal requirements submitted by the system. If the State approves the alternative mi nimum TOC removal (Step 2) requirements, the State may make those requirements retroactive for the purposes of determining compliance. Until the State approves the alternate minimum TOC removal (Step 2) requirements, the system must meet the Step 1 TOC removals contained in paragraph (b)(2) of this section.
(4) Alternate minimum TOC removal (Step 2) requirements. Applications made to the State by enhanced coagulation systems for approval of alternate mini mum TOC removal (Step 2) requirements under paragraph (b)(3) of this section must include, at a minimum, results of bench- or pilot-scale testing conducted under paragraph (b)(4)(i) of this section. The submitted bench- or pilot-scale testing must be used to determine the alternate enhanced coagulation level.
(i) Alternate enhanced coagulation level is defined as coagulation at a coagulant dose and pH as determined by the method described in paragraphs (b)(4)(i) through (v) of this section such that an incremental addition of 10 mg/L of alum (or equivalent amount of ferric salt) results in a TOC removal of ≤ 0.3 mg/L. The percent removal of TOC at this point on the “TOC removal versus coagulant dose” curve is then defined as the minimum TOC remova l required for the system. Once approved by the State, this minimum requirement supersedes the minimum TOC removal required by the table in paragraph (b)(2) of this section. This requirement will be effective until such time as the State approves a new value based on the results of a new bench- and pilot-scale test. Failure to achieve State-set alternative minimum TOC removal levels is a violation of National Primary Drinking Water Regulations.
(ii) Bench- or pilot-scale testing of enhanced co agulation must be conduct ed by using representative water samples and adding 10 mg/L increments of alum (or equivalent amounts of ferric salt) until the pH is reduced to a level less than or equal to the enhanced coagulation Step 2 target pH shown in the following table:
Enhanced Coagulation Step 2 target pH

(iii) For waters with alkalinities of less than 60 mg/L for which addition of small amounts of alum or equivalent addition of iron coagulant drives the pH below 5.5 before significant TOC removal occurs, the system must add necessary chemical s to maintain the pH between 5.3 and 5.7 in samples until the TOC removal of 0.3 mg/L per 10 mg/L alum added (or equivalant addition of iron coagulant) is reached.
(iv) The system may operate at any coagulant dose or pH necessary (consistent with other NPDWRs) to achieve the minimum TOC percent removal approved under paragraph (b)(3) of this section.

(v) If the TOC removal is consistently less than 0.3 mg/L of TOC per 10 mg/L of incremental alum dose at all dosages of alum (or equivalant addition of iron coagulant), the water is deemed to contain TOC not amenable to enhanced coagulation. The system may then apply to the State for a waiver of enhanced coagulation requirements.
(c) Compliance calculations. (1) Subpart H systems other than those iden tified in paragraph (a)(2) or (a) (3) of this section must comply with requirements contained in paragraph (b)(2) or (b)(3) of this section. Systems must calculate compliance quarterly, beginning after the system has collected 12 months of data, by determining an annual average using the following method:
(i) Determine actual monthly TOC percent removal, equal to:
(1

− (treated water TOC/source water TOC)) × 100
(ii) Determine the required monthly TOC percent remova l (from either the table in paragraph (b)(2) of this section or from paragraph (b)(3) of this section).

(iii) Divide the value in paragraph (c )(1)(i) of this section by the value in paragraph (c)(1)(ii) of this section.
(iv) Add together the results of paragraph (c)(1)(iii) of this section for the last 12 months and divide by 12.
(v) If the value calculated in paragra ph (c)(1)(iv) of this section is less than 1.00, the system is not in compliance with the TOC percent removal requirements.
(2) Systems may use the provisions in paragraphs (c)(2)(i) through (v) of this section in lieu of the calculations in paragraph (c)(1)(i ) through (v) of this section to determine compliance with TOC percent removal requirements.
(i) In any month that the system's treated or source water TOC level, measured according to §141.131 (d)(3), is less than 2.0 mg/L, the system may assign a monthly value of 1.0 (in lieu of the value calculated in paragraph (c)(1)(iii) of this section) when calculating compliance under the provisions of paragraph (c)(1) of this section.

(ii) In any month that a system prac ticing softening removes at least 10 mg/L of magnesium hardness (as CaCO 3 ), the system may assign a monthly value of 1.0 (in lieu of the value calculated in paragraph (c)(1)(iii) of this section) when calculating compli ance under the provisions of paragraph (c)(1) of this section.
(iii) In any month that the system's source water SUVA, prior to any treatment and measured according to §141.131(d)(4), is ≤ 2.0 L/mg-m, the system may assign a monthly value of 1.0 (in lieu of the value calculated in paragraph (c)(1)(iii) of this section) when calculating compliance under the provisions of paragraph (c)(1) of this section. 

## Alkalinity (mg/L as CaCO 3 

## ) Target pH 0–60 5.5 >60–120 6.3 >120–240 7.0 >240 7.5 

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...(iv) In any month that the system's finished wate r SUVA, measured according to §141.131(d)(4), is ≤ 2.0 L/mg-m, the system may assign a monthly value of 1.0 (in lieu of the value calculated in paragraph (c)(1) (iii) of this section) when calculat ing compliance under the provisions of paragraph (c)(1) of this section.

(v) In any month that a system practicing enhanced softening lowers alkalinity below 60 mg/L (as CaCO 3 ), the system may assign a monthly value of 1.0 (in lieu of the value calculated in paragraph (c) (1)(iii) of this section) when calculating compliance under the provisions of paragraph (c)(1) of this section.
(3) Subpart H systems using conventional treatment may also comply with the requirements of this section by meeting the criteria in paragraph (a)(2) or (3) of this section.

(d) Treatment technique requirem ents for DBP precursors. The Administrator identi fies the following as treatment techniques to control the level of disinfecti on byproduct precursors in drinking water treatment and distribution systems: For Subpart H systems using conventional treatment, enhanced coagulation or enhanced softening.

[63 FR 69466, Dec. 16, 1998, as amended at 66 FR 3779, Jan. 16, 2001; 71 FR 482, Jan. 4, 2006]


### Subparts M–N [Reserved]

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### Subpart O—Consumer Confidence Reports

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### Source: 63 FR 44526, Aug. 19, 1998, unless otherwise noted.
§ 141.151 Purpose and applicability of this subpart.

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(a) This subpart establishes the minimum requirement s for the content of annual reports that community water systems must deliver to their customers. These reports must contain information on the quality of the water delivered by the systems and characterize the risks (if any) from exposure to contaminants detected in the drinking water in an accurate and understandable manner.
(b) Notwithstanding the provisions of §141.3, this subpart applies on ly to community water systems.
(c) For the purpose of this subpart, customers are defined as billing units or service connections to which water is delivered by a community water system.
(d) For the purpose of this subpart, detected means: at or above the levels prescribed by §141.23(a)(4) for inorganic contaminants, at or above the levels pr escribed by §141.24(f)(7) for the contaminants listed in §141.61(a), at or above the levels prescribed by §141.24(h)(18) for the contaminants listed in §141.61 (c), at or above the levels prescribed by §141.131( b)(2)(iv) for the contaminants or contaminant groups listed in §141.64, and at or above the levels prescribed by §141.25(c) for radioactive contaminants.
(e) A State that has primary enforcement responsibility may adopt by rule, after notice and comment, alternative requirements for the form and content of the reports. The alternative requirements must provide the same type and amount of information as required by §§141.153 and 141.154, and must be designed to achieve an equivalent level of public i nformation and education as would be achieved under this subpart.
(f) For purpose of §§141.154 and 141.155 of this subpart, the term “primacy agency” refers to the State or tribal government entity that has jurisdiction over, and primary enforcement responsibility for, public water systems, even if that government does not have interim or final primary enforcement responsibility for this rule. Where the State or tribe does not have primary enforcement responsibility for public water systems, the term “primacy agency” refe rs to the appropriate EPA regional office.

[63 FR 44526, Aug. 19, 1998, as amended at 71 FR 483, Jan. 4, 2006]


### § 141.152 Effective dates.

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(a) The regulations in this subpart s hall take effect on September 18, 1998.
(b) Each existing community water system must deliv er its first report by October 19, 1999, its second report by July 1, 2000, and subsequent reports by July 1 annually thereafter. The first report must contain data collected during, or prior to, calendar year 1998 as prescribed in §141.153(d)(3). Each report thereafter must contain data collected duri ng, or prior to, the previous calendar year.
(c) A new community water system must deliver its firs t report by July 1 of the year after its first full calendar year in operation and annually thereafter.

(d) A community water system that sells water to another community water system must deliver the applicable information required in §141.153 to the buyer system:
(1) No later than April 19, 1999, by April 1, 2000, and by April 1 annually thereafter or
(2) On a date mutually agreed upon by the seller and the purchaser, and specifically included in a contract between the parties.


### § 141.153 Content of the reports. 

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...top
(a) Each community water system must provide to its customers an annual report that contains the information specified in this section and §141.154.
(b) Information on the source of the water delivered:

(1) Each report must identify the source(s) of the water delivered by the community water system by providing information on:
(i) The type of the water: e.g., surface water, ground water; and
(ii) The commonly used name (if any) and location of the body (or bodies) of water.

(2) If a source water assessment has been comple ted, the report must notify consumers of the availability of this information and the means to obtain it. In addition, systems are encouraged to highlight in the report significant sources of contamination in the source water area if they have readily available information. Where a system has rece ived a source water assessment from the primacy agency, the report must include a brief summary of the system's susceptibility to potential sources of contamination, using language provided by the primacy agency or written by the operator.
(c) Definitions. (1) Each report must include the following definitions:

(i) Maximum Contaminant Level Goal or MCLG: The level of a contaminant in drinking water below which there is no known or expe cted risk to health. MCLGs allow for a margin of safety.
(ii) Maximum Contaminant Level or MCL: The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as feasib le using the best available treatment technology.
(2) A report for a community water system operating under a variance or an exemption issued under §1415 or 1416 of SDWA must include the following definition: Variances and Exemptions: State or EPA permission not to meet an MCL or a treatment technique under certain conditions.
(3) A report that contains data on contaminants that EPA regulates using any of the following terms must include the applicable definitions:

(i) Treatment Technique: A required process intended to reduce the level of a contaminant in drinking water.
(ii) Action Level: The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow.
(iii) Maximum residual disinfectant level goal or MRDLG: The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contaminants.
(iv) Maximum residual disinfectant level or MRDL: The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.
(d) Information on detected contaminants.

(1) This sub-section specifies the requirements for information to be included in each report for contaminants subject to mandatory monitoring (except Cryptosporidium ). It applies to:
(i) Contaminants subject to a MCL, action level, maximum residual disinfectant level, or treatment technique (regulated contaminants).
(ii) Contaminants for which monitoring is required by §141.40 (unregulated contaminants); and

(iii) Disinfection by-products or microbial contam inants for which monitoring is required by §§141.142 and 141.143, except as provided under paragraph (e)(1) of this section, and which are detected in the finished water.

(2) The data relating to these contaminants must be displayed in one table or in several adjacent tables. A ny additional monitoring results wh ich a community water system chooses to include in its report must be displayed separately.
(3) The data must be derived from data collected to comply with EPA and State monitoring and analytical requirements during cal endar year 1998 for the first report and subsequent calendar years thereafter except that:
(i) Where a system is allowed to monitor for regul ated contaminants less often than once a year, the table(s) must include the date and results of the most recent sampling and the report must include a brief statement indicating that the data presented in the report are from the most recent testing done in accordance with the regulations. No data older than 5 years need be included.
(ii) Results of monitoring in compliance with §§141.142 and 141.143 need only be included for 5 years from the date of last sample or until any of the detected contaminants becomes regulated and subject to routine monitoring requirements, whichever comes first.
(4) For detected regulated contaminants (listed in appendix A to this subpart), the table(s) must contain:

(i) The MCL for that contaminant ex pressed as a number equal to or greater than 1.0 (as provided in appendix A to this subpart);
(ii) The MCLG for that contaminant expre ssed in the same units as the MCL;
(iii) If there is no MCL for a detected contaminant, the table must indicate that there is a treatment technique, or specify the action level, applicable to that contaminant, and the report must include the definitions for treatment technique and/or action level, as appropriate, specified in paragraph (c)(3) of 

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...this section;
(iv) For contaminants s ubject to an MCL, except turbidity and to tal coliforms, the highest contaminant level used to determine compliance with an NPDWR and the range of detected levels, as follows:
(A) When compliance with the MCL is determined annually or less frequently: The highest detected level at any sampling point and the range of detected leve ls expressed in the same units as the MCL.
(B) When compliance with the MCL is determined by calculating a running annual average of all samples taken at a monitoring location: the highest average of any of the monitoring locations and the range of all monitoring locations ex pressed in the same units as the MCL. For the MCLs for TTHM and HAA5 in §141.64(b)(2), systems must include the hi ghest locational running annual average for TTHM and HAA5 and the range of individual sample results for all monitoring locations expressed in the same units as the MCL. If more than one location exceeds the TTHM or HAA5 MCL, the system must include the locational running annual averages for all locations that exceed the MCL.
(C) When compliance with the MCL is determined on a system-wide basis by calculating a running annual average of all samples at all monitoring lo cations: the average and range of detection expressed in the same units as the MCL. The system is required to include individual sample results for the IDSE conducted under subpart U of this part when determining the range of TTHM and HAA5 results to be reported in the annual consumer confidence reportfor the calendar year that the IDSE samples were taken.


### Note to paragraph (d)(4)(iv): When rounding of results to determine compliance with the MCL is allowed by the regulations, rounding should be done prior to multiplying the results by the factor listed in appendix A of this subpart.

(v) For turbidity.
(A) When it is reported pursuant to §141 .13: The highest average monthly value.
(B) When it is reported pursuant to the requirements of §141.71: the highest monthly value. The report should include an explanation of the reasons for measuring turbidity.
(C) When it is reported pursuant to §141.73 or §141.173 or §141.551: the highest single measurement and the lowest monthly percentage of samples meeting the turbidity limits specified in §141.73 or §141.173, or §141.551 for the filtration technology bei ng used. The report should include an explanation of the reasons for measuring turbidity;

(vi) For lead and copper: the 90th percentile value of the most recent round of sampling and the number of sampling sites exceedi ng the action level;
(vii) For total coliform:
(A) The highest monthly number of positive samples for systems collecting fewer than 40 samples per month; or
(B) The highest monthly percentage of positive samples for systems collecting at least 40 samples per month;
(viii) For fecal coliform: The total number of positive samples; and
(ix) The likely source(s) of detected contaminants to the best of the operator's knowledge. Specific information regarding contaminants may be avai lable in sanitary surveys and source water assessments, and should be used when available to the operator. If the operator lacks specific information on the likely source, the report must include one or more of the typical sources for that contaminant listed in appendix A to this subpart that is most applicable to the system.
(5) If a community water system di stributes water to its customers from multiple hydraulically independent distribution systems that are fed by different raw water sources, the table should contain a separate column for each service area and the report should identify each separate distribution system. A lternatively, systems could produce separate reports tailored to include data for each service area.
(6) The table(s) must clearly identify any data in dicating violations of MC Ls, MRDLs, or treatment techniques, and the report must contain a clear and readily understandable expl anation of the violation including: the length of the violation, the potential adverse health effects, an d actions taken by the system to address the violation. To describe the p otential health effects, the system must use the relevant language of appendix A to this subpart.
(7) For detected unregulated contaminants for which monitoring is required (except Cryptosporidium ), the table(s) must contain the average and range atwhich the contaminant was detected. The report may include a brief explanation of the reasons fo r monitoring for unregulated contaminants.
(e) Information on Cryptosporidium, radon, and other contaminants:
(1) If the system has performed any monitoring for Cryptosporidium, including monitoring performed to satisfy the requirements of §141.143, which indicates that Cryptosporidium may be present in the source water or the finished water, the report must include:

(i) A summary of the results of the monitoring; and
(ii) An explanation of the significance of the results.
(2) If the system has performed any monitoring for radon which indicates that radon may be present in the finished water, the report must include:

(i) The results of the monitoring; and
(ii) An explanation of the significance of the results.
(3) If the system has performed additional monitoring which indic ates the presence of other contaminants in the finished water, EPA strongly encourages systems to report any results which may 

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...indicate a health concern. To determine if results may indicate a health concern, EPA recommends that systems find out if EPA has proposed an NPDWR or i ssued a health advisory for that contaminant by calling the Safe Drinking Water Hotline (800–426–4791). EPA considers detects above a proposed MCL or health advisory level to indicate possible heal th concerns. For such contaminants, EPA recommends that the report include:
(i) The results of the monitoring; and
(ii) An explanation of the significance of the re sults noting the existence of a health advisory or a proposed regulation.
(f) Compliance with NPDWR. In addition to the requ irements of §141.153(d)(6), the report must note any violation that occurred during the year covered by the report of a requirement listed below, and include a clear and readily understandable explanation of the violation, any potential adverse health effects, and the steps the system has tak en to correct the violation.
(1) Monitoring and reporting of compliance data;

(2) Filtration and disinfection prescribed by sub part H of this part. For systems which have failed to install adequate filtration or disinfection equipment or processes, or have had a failure of such equipment or processes which constitutes a violation, the report must include the following language as part of the explanation of potential adverse heal th effects: Inadequately treated water may contain disease-causing organisms. These organisms inclu de bacteria, viruses, and parasites which can cause symptoms such as nausea, cramps, diarrhea, and associated headaches.
(3) Lead and copper control requirements prescribed by subpart I of this part. For systems that fail to take one or more actions prescribed by §§141.80(d), 141.81, 141.82, 141.83 or 141.84, the report must include the applicable language of appendix A to this subpart for lead, copper, or both.

(4) Treatment techniques for Acrylamide and Epichlorohydrin prescribed by subpart K of this part. For systems that violate the requirements of subpart K of this part, the report must include the relevant language from appendix A to this subpart.

(5) Recordkeeping of compliance data.
(6) Special monitoring requirements prescribed by §§141.40 and 141.41; and
(7) Violation of the terms of a variance, an exempti on, or an administrative or judicial order.
(g) Variances and Exemptions. If a system is operating under the terms of a variance or an exemption issued under §1415 or 1416 of SDWA, the report must contain:
(1) An explanation of the reasons for the variance or exemption;
(2) The date on which the variance or exemption was issued;

(3) A brief status report on the s teps the system is taking to install treatment, find alternative sources of water, or otherwise comply with the terms and schedules of the variance or exemption; and
(4) A notice of any opportunity for public input in the review, or renewal, of the variance or exemption.
(h) Additional information:

(1) The report must contain a brief explanation regarding contaminants which may reasonably be expected to be found in drinking water includi ng bottled water. This explanation may include the language of paragraphs (h)(1) (i) through (iii) or systems may use their own comparable language. The report also must include the language of paragraph (h)(1)(iv) of this section.

(i) The sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it dissolves naturally-occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or from human activity.

(ii) Contaminants that may be present in source water include:
(A) Microbial contaminants, such as viruses and bacteria, which may come from sewage treatment plants, septic systems, agricultural livestock operations, and wildlife.
(B) Inorganic contaminants, such as salts and metals, which can be naturally-occurring or result from urban stormwater runoff, industrial or domestic wast ewater discharges, oil and gas production, mining, or farming.
(C) Pesticides and herbicides, which may come from a variety of so urces such as agriculture, urban stormwater runoff, and residential uses.

(D) Organic chemical contaminants, including synthetic and volatile organic chemicals, which are byproducts of industrial processes and petroleum product ion, and can also come from gas stations, urban stormwater runoff, and septic systems.
(E) Radioactive contaminants, which can be naturally-occurring or be the result of oil and gas production and mining activities.
(iii) In order to ensure that tap water is safe to drink, EPA prescribes regulations which limit the amount of certain contaminants in water provided by public water systems. FDA regulations establish limits for contaminants in bottled water which must provide the same protection for public health.
(iv) Drinking water, including bottled water, ma y reasonably be expected to contain at least small amounts of some contaminants. The presence of co ntaminants does not necess arily indicate that water poses a health risk. More information about contam inants and potential health e ffects can be obtained by calling the Environmental Protection Agency's Safe Drinking Water Hotline (800–426–4791).
(2) The report must include the telephone number of the owner, operator, or designee of the community 

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(3) In communities with a large proportion of non- English speaking residents, as determined by the Primacy Agency, the report must contain information in the appropriate language(s) regarding the importance of the report or contain a telephone number or address where such residents may contact the system to obtain a translated copy of the re port or assistance in the appropriate language.
(4) The report must include information (e.g., time and place of regularly scheduled board meetings) about opportunities for public participation in deci sions that may affect the quality of the water.
(5) The systems may include such additional inform ation as they deem necessary for public education consistent with, and not detracting from, the purpose of the report.
(6) Systems required to comply with subpart S. (i) Any ground water system that receives notice from the State of a significant deficiency or notice from a laboratory of a fecal indicator-positive ground water source sample that is not invalidated by the State under §141.402(d) must inform its customers of any significant deficiency that is uncorrected at the time of the next report or of any fecal indicator-positive ground water source sample in the next report. The system must continue to inform the public annually until the State determines that particular significant deficiency is corrected or the fecal contamination in the ground water source is addressed under §141.403(a). Each report must include the following elements.
(A) The nature of the particular signi ficant deficiency or the source of the fecal contamination (if the source is known) and the date the significant deficiency was identified by the State or the dates of the fecal indicator-positive ground water source samples;
(B) If the fecal contamination in the ground water source has been addressed under §141.403(a) and the date of such action;

(C) For each significant deficiency or fecal contamination in the ground water source that has not been addressed under §141.403(a), the State-approved plan and schedule for correction, including interim measures, progress to date, and any interim measures completed; and
(D) If the system receives notice of a fecal indicator-posit ive ground water source sample that is not invalidated by the State under §141.402(d), the potential health effects using the health effects language of Appendix A of subpart O.
(ii) If directed by the State, a sy stem with significant deficiencies that have been corrected before the next report is issued must inform its customers of the significant deficiency, how the deficiency was corrected, and the date of correction under paragraph (h)(6)(i) of this section.

[63 FR 44526, Aug. 19, 1998, as amended at 63 FR 69516, Dec. 16, 1998; 64 FR 34733, June 29, 1999; 65 FR 26022, May 4, 2000; 67 FR 1836, Jan. 14, 2002; 71 FR 483, Jan. 4, 2006; 71 FR 65651, Nov. 8, 2006]


### § 141.154 Required additional health information.

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(a) All reports must prominently display the following language: Some people may be more vulnerable to contaminants in drinking water than the general population. Immuno-compromised persons such as persons with cancer undergoing chemotherapy, pers ons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants c an be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. EPA/CDC guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline (800–426–4791).
(b) Ending in the report due by July 1, 2001, a system which detects arsenic at levels above 0.025 mg/L, but below the 0.05 mg/L, and beginning in the report due by July 1, 2002, a system that detects arsenic above 0.005 mg/L and up to and including 0.010 mg/L:
(1) Must include in its report a short informatio nal statement about arsenic, using language such as: While your drinking water meets EPA's standard for arsenic, it does contain low levels of arsenic. EPA's standard balances the current understanding of arseni c's possible health effects against the costs of removing arsenic from drinking water. EPA continues to research the health effects of low levels of arsenic, which is a miner al known to cause cancer in humans at high concentrations and is linked to other health effects such as skin damage and circulatory problems.
(2) May write its own educational statement, but on ly in consultation with the Primacy Agency.
(c) A system which detects nitrate at leve ls above 5 mg/l, but below the MCL:
(1) Must include a short informational statement about the impacts of nitrate on children using language such as: Nitrate in drinking water at levels above 10 ppm is a health risk for infants of less than six months of age. High nitrate levels in drinking water can cause blue baby syndrome. Nitrate levels may rise quickly for short periods of time because of rainfall or agricultural activity. If you are caring for an infant you should ask advice from your health care provider.
(2) May write its own educational statement, but on ly in consultation with the Primacy Agency.
(d) Every report must include the following lead-specific information:

(1) A short informational statement about lead in drinking water and its effects on children. The statement must include the following information:


### If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children. Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. [NAME OF UTILITY] is responsible for providing high quality drinking water, but cannot control the variety of materials used in plumbing components. When your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your tap for 30 seconds to 2 minutes before using water for drinking or cooking. If you are concerned about lead in your water, you 

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### may wish to have your water tested. Information on lead in drinking water, testing methods, and steps you can take to minimize exposure is available from the Safe Drinking Water Hotline or at http://www.epa.gov/safewater/lead.

(2) A system may write its own educational state ment, but only in cons ultation with the State.
(e) Community water systems that detect TTHM above 0.0 80 mg/l, but below the MCL in §141.12, as an annual average, monitored and calculated under the prov isions of §141.30, must include health effects language for TTHMs prescribed by appendix A.
(f) Beginning in the report due by July 1, 2002, and ending January 22, 2006, a community water system that detects arsenic above 0.010 mg/L and up to and including 0.05 mg/L must include the arsenic health effects language prescribed by appendix A to subpart O of this part.

[63 FR 44526, Aug. 19, 1998, as amended at 63 FR 69475, Dec. 16, 1998; 64 FR 34733, June 29, 1999; 65 FR 26023, May 4, 2000; 66 FR 7064, Jan. 22, 2001; 68 FR 14506, Mar. 25, 2003; 72 FR 57820, Oct. 10, 2007]


### § 141.155 Report delivery and recordkeeping.

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(a) Except as provided in paragraph (g) of this se ction, each community water system must mail or otherwise directly deliver one copy of the report to each customer.
(b) The system must make a good faith effort to re ach consumers who do not get water bills, using means recommended by the primacy agency. EPA expects that an adequate good faith effort will be tailored to the consumers who are served by the system but are not bill-paying customers, such as renters or workers. A good faith effort to reach consumers would include a mix of methods appropriate to the particular system such as: Posting the reports on the Internet; mailing to postal patrons in metropolitan areas; advertising the availability of the report in the news media; publication in a local newspaper; posting in publicplaces such as cafeteri as or lunch rooms of public buildings; delivery of multiple copies for distribution by single-biller customers such as apartment buildings or large private employers; delivery to community organizations.
(c) No later than the date the system is required to dist ribute the report to its customers, each community water system must mail a copy of the report to the primacy agency, followed within 3 months by a certification that the report has been distributed to cu stomers, and that the information is correct and consistent with the compliance monitoring data previously submitted to the primacy agency.
(d) No later than the date the system is required to distribute the report to its customers, each community water system must deliver the report to any other agency or cleari nghouse identified by the primacy agency.
(e) Each community water system must make its reports available to the public upon request.
(f) Each community water system serving 100,000 or more persons must post its current year's report to a publicly-accessible site on the Internet.
(g) The Governor of a State or his designee, or the Tribal Leader where the tribe has met the eligibility requirements contained in §142.72 for the purposes of waiving the mailing requirement, can waive the requirement of paragraph (a) of this section for community water systems serving fewer than 10,000 persons. In consultation with the tribal governme nt, the Regional Administrator may waive the requirement of §141.155(a) in areas in Indian country where no tribe has been deemed eligible.

(1) Such systems must:
(i) Publish the reports in one or more local newspa pers serving the area in which the system is located;
(ii) Inform the customers that the reports will not be mail ed, either in the newspapers in which the reports are published or by other means approved by the State; and
(iii) Make the reports avail able to the public upon request.
(2) Systems serving 500 or fewer persons may forego the requirements of paragraphs (g)(1)(i) and (ii) of this section if they provide notice at least once per year to their customers by mail, door-to-door delivery or by posting in an appropriate location that the report is available upon request.
(h) Any system subject to this subpart must retain copi es of its Consumer Confidence Report for no less than 3 years.

[63 FR 44526, Aug. 19, 1998, as amended at 65 FR 26023, May 4, 2000]


### Appendix A to Subpart O of Part 141—Regulated Contaminants

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## Contaminant (units) Traditional MCL in mg/L To convert for CCR, multiply by MCL in CCR units MCLG Major sources in drinking water Health effects language Microbiological contaminants: Total Coliform Bacteria MCL: (systems that collect ≥ 40 samples/month) 5% of monthly samples are MCL: (systems that collect ≥ 40 samples/month) 5% of monthly samples are 0 Naturally present in the environment Coliforms are bacteria that are naturally present in the environment and are used as an indicator that other, potentially-harmful, 

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## positive; (systems that collect <40 samples/month) 1 positive monthly sample positive; (systems that collect <40 samples/month) 1 positive monthly sample bacteria may be present. Coliforms were found in more samples than allowed and this was a warning of potential problems. Fecal coliform and E. coli 0 0 0 Human and animal fecal waste Fecal coliforms and E. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, andpeople with severelycompromised immune systems. Fecal Indicators (enterococci or coliphage) TT TT N/A Human and animal fecal waste Fecal indicators are microbes whose presence indicates that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term health effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, and people with severely compromised immune systems. Total organic carbon (ppm) TT TT N/A Naturally present in the environment Total organic carbon (TOC) has no health effects. However, total organic carbon provides a medium for the formation of disinfection by products. These byproducts include trihalomethanes (THMs) and haloacetic acids (HAAs). Drinking water containing these byproducts in excess of the MCL may lead to adverse health effects, liver or kidney problems, or nervous system effects, and may lead to an increased risk of getting
cancer. Turbidity (NTU) TT TT N/A Soil r unoff Turbidity has no health effects. However, turbidity can interfere with disinfection and provide a medium for microbial growth. Turbidity may indicate the presence of disease-causing organisms. These organisms include bacteria, viruses, and parasites that can cause symptoms such as nausea, cramps, diarrhea and associated headaches. Radioactive contaminants: Beta/photon emitters 4 mrem/yr

− 4 0 Decay of natural Certain minerals are 

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## (mrem/yr) and man-made deposits radioactive and may emit forms of radiation known as photons and beta radiation. Some people who drink water containing beta particle and photon radioactivity in excess of the MCL over many years may have an increased risk of getting cancer. Alpha emitters (pCi/L) 15 pCi/L

− 15 0 Erosion of natural deposits Certain minerals are radioactive and may emit a form of radiation known as alpha radiation. Some people who drink water containing alpha emitters in excess of the MCL over many years may have an increased risk of getting
cancer. Combined radium (pCi/L) 5 pCi/L

− 5 0 Erosion of natural deposits Some people who drinkwater containing radium226 or -228 in excess of the MCL over many years may have an increased risk of getting cancer. Uranium (pCi/L) 30 μg/L

− 30 0 Erosion of natural deposits Some people who drink water containing uranium in excess of the MCL over many years may have an increased risk of getting cancer and kidney toxicity. Inorganic contaminants: Antimony (ppb) .006 1000 6 6 Discharge from petroleum refineries; fire retardants; ceramics; electronics; solder Some people who drink water containing antimony well in excess of the MCL over many years could experience increases in blood cholesterol and decreases in blood sugar. Arsenic (ppb) 1 

## 0.010 1000 1 

## 10. 1 

## 0 Erosion of natural deposits; Runoff from orchards; Runoff from glass and electronics production wastes Some people who drink water containing arsenic in excess of the MCL over many years could experience skin damage or problems with their circulatory system, and may have an increased risk of getting cancer. Asbestos (MFL) 7 MFL 7 7 Decay of asbestos cement water mains; Erosion of natural deposits Some people who drink water containing asbestos in excess of the MCL over many years may have an increased risk of developing benign intestinal polyps. Barium (ppm) 2 2 2 Discharge of drilling wastes; Discharge from metal refineries; Erosion of natural deposits Some people who drink water containing barium in excess of the MCL over many years could experience an increase in their blood pressure. Beryllium (ppb) .004 1000 4 4 Discharge from metal refineries and coal-burning factories; Discharge from electrical, aerospace, and defense industries Some people who drink water containing beryllium well in excess of the MCL over many years could develop intestinal lesions

Bromate (ppb) .010 1000 10 0 By-product of drinkig water disinfection Some people who drink water of containing bromate in excess of the MCL over many years may have an increased risk of 

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## getting cancer. Cadmium (ppb) .005 1000 5 5 Corrosion of galvanized pipes; Erosion of natural deposits; Discharge from metal refineries; Runoff from waste batteries and paints Some people who drink water containing cadmium in excess of the MCL over many years could experience kidney damage.

Chloramines (ppm) MRDL=4 MRDL =4 MRDLG=4 Water additive used to control microbes Some people who use water containing chloramines well in excess of the MRDL could experience irritating effects to their eyes and nose. Some people who drink water containing chloramines well in excess of the MRDL could experience stomach discomfort or anemia. Chlorine (ppm) MRDL=4 MRDL=4 MRDLG=4 Water additive used to control microbes Some people who use water containing chlorine well in excess of the MRDL could experience irritating effects to their eyes and nose. Some people who drink water containing chlorine well in excess of the MRDL could experience stomach discomfort. Chlorine dioxide (ppb) MRDL=.8 1000 MRDL=800 MRDLG=800 Water additive used to control micorbes Some infants and young children who drink water chlorine dioxide in excess of the MRDL could experience nervous system effects. Similar effects may occur in fetuses of pregnant women who drink water containing chlorine dioxide in excess of the MRDL. Some people may experience anemia. Chlorite (ppm) 1 1 0.8 By-product of drinking water disinfection Some infants and young children who drink water containing chlorite in excess of the MCL could experience nervous system effects. Similar effects may occur in fetuses of pregnant women who drink water containing chlorite in excess of the MCL. Some people may experience anemia. Chromium (ppb) .1 1000 100 100 Discharge from steel and pulp mills; Erosion of natural deposits Some people who use water containing chromium well in excess of the MCL over many years could experience allergic dermatitis. Copper (ppm) AL=1.3 AL=1.3 1.3 Corrosion of household plumbing systems; Erosion of natural deposits Copper is an essential nutrient, but some people who drink water containing copper in excess of the action level over a relatively short amount of time could experience gastrointestinal distress. Some people who drink water containing copper in excess of the action level over many years could suffer liver or kidney 

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## damage. People with Wilson's disease should consult their personal doctor. Cyanide (ppb) .2 1000 200 200 Discharge from steel/metal factories; Discharge from plastic and fertilizer factories Some people who drink water containing cyanide well in excess of the MCL over many years could experience nerve damage or problems with their thyroid. Fluoride (ppm) 4 4 4 Erosion of natural deposits; Water additive which promotes strong teeth; Discharge from fertilizer and aluminum factories Some people who drink water containing fluoride in excess of the MCL over many years could get bone disease, including pain and tenderness of the bones. Fluoride in drinking water at half the MCL or more may cause mottling of children's teeth, usually in children less than nine years old. Mottling, also known as dental fluorosis, may include brown staining and/or pitting of the teeth, and occurs only in developing teeth before they erupt from the gums. Lead (ppb) AL=.015 1000 AL=15 0 Corrosion of household plumbing systems; Erosion of natural deposits Infants and children who drink water containing lead in excess of the action level could experience delays in their physical or mental development. Children could show slight deficits in attention span and learning abilities. Adults who drink this water over many years could develop kidney problems or high blood pressure. Mercury [inorganic] (ppb) .002 1000 2 2 Erosion of natural deposits; Dis charge from refineries and factories; Runoff from landfills; Runoff from cropland Some people who drink water containing inorganic mercury well in excess of the MCL over many years could experience kidney damage.

Nitrate (ppm) 10 10 10 Runoff from fertilizer use; Leaching from septic tanks, sew age; Erosion of natural deposits Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue baby syndrome. Nitrite (ppm) 1 1 1 Runoff from fertilizer use; Leaching from septic tanks, sew age; Erosion of natural deposits Infants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue baby syndrome. Selenium (ppb) .05 1000 50 50 Discharge from petroleum and metal refineries; Erosion of natural deposits; Discharge from mines Selenium is an essential nutrient. However, some people who drink water containing selenium in excess of the MCL over many years could experience hair or 

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## fingernail losses, numbness in fingers or toes, or problems with their circulation.Thallium (ppb) .002 1000 2 0.5 Leaching from oreprocessing sites; Discharge from electronics, glass, and drug factories Some people who drink water containing thallium in excess of the MCL over many years could experience hair loss, changes in their blood, or problems with their kidneys, intestines, or liver. Synthetic organic contaminants including pesticides and herbicides: 2,4-D (ppb) .07 1000 70 70 Runoff from herbicide used on row crops Some people who drink water containing the weed killer 2,4-D well in excess of the MCL over many years could experience problems with their kidneys, liver, or adrenal glands. 2,4,5-TP [Silvex](ppb) .05 1000 50 50 Residue of banned herbicide Some people who drink water containing silvex in excess of the MCL over many years could experience liver problems. Acrylamide TT TT 0 Added to water during sewage/wastewater treatment Some people who drink water containing high levels of acrylamide over a long period of time could have problems with their nervous system or blood, and may have an increased risk of getting
cancer. Alachlor (ppb) .002 1000 2 0 Runoff from herbicide used on row crops Some people who drink water containing alachlor in excess of the MCL over many years could have problems with their eyes, liver, kidneys, or spleen, or experience anemia, and may have an increased risk of getting cancer. Atrazine (ppb) .003 1000 3 3 Runoff from herbicide used on row crops Some people who drink water containing atrazine well in excess of the MCL over many years could experience problems with their cardiovascular system or reproductive difficulties. Benzo(a)pyrene [PAH] (nanograms/l) .0002 1,000,000 200 0 Leaching from linings of water storage tanks and distribution lines Some people who drink water containing benzo(a) pyrene in excess of the MCL over many years may experience reproductive difficulties and may have an increased risk of getting
cancer. Carbofuran (ppb) .04 1000 40 40 Leaching of soil fumigant used on rice and alfalfa Some people who drink water containing carbofuran in excess of the MCL over many years could experience problems with their blood, or nervous or reproductive systems. Chlordane (ppb) .002 1000 2 0 Residue of banned termiticide Some people who drink water containing chlordane in excess of the MCL over many years could experience problems with their liver or nervous system, and may have an increased risk of getting 

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## cancer. Dalapon (ppb) .2 1000 200 200 Runoff from herbicide used on rights of way Some people who drink water containing dalapon well in excess of the MCL over many years could experience minor kidney changes. Di(2-ethylhexyl) adipate (ppb) .4 1000 400 400 Discharge from chemical factories Some people who drink water containing di(2- ethylhexyl) adipate well in excess of the MCL over many years could experience toxic effects such as weight loss, liver enlargement or possible reproductive difficulties. Di(2-ethylhexyl) phthalate (ppb) .006 1000 6 0 Discharge from rubber and chemical factories Some people who drink water containing di(2- ethylhexyl) phthalate well in excess of the MCL over many years may have problems with their liver, or experience reproductive difficulties, and may have an increased risk of getting
cancer. Dibromochloropropane (ppt) .0002 1,000,000 200 0 Runoff/leaching from soil fumigant used on soybeans, cotton, pineapples, and orchards Some people who drink water containing DBCP in excess of the MCL over many years could experience reproductive problems and may have an increased risk of getting
cancer. Dinoseb (ppb) .007 1000 7 7 Runoff from herbicide used on soybeans and vegetables Some people who drink water containing dinoseb well in excess of the MCL over many years could experience reproductive difficulties. Diquat (ppb) .02 1000 20 20 Runoff from herbicide use Some people who drink water containing diquat in excess of the MCL over many years could get cataracts. Dioxin [2,3,7,8-TCDD] (ppq) .00000003 1,000,000, 000 30 0 Emissions from waste incineration and other combustion; Discharge from chemical factories Some people who drink water containing dioxin in excess of the MCL over many years could experience reproductive difficulties and may have an increased risk of getting
cancer. Endothall (ppb) .1 1000 100 100 Runoff from herbicide use Some people who drink water containing endothall in excess of the MCL over many years could experience problems with their stomach or intestines. Endrin (ppb) .002 1000 2 2 Residue of banned insecticide Some people who drink water containing endrin in excess of the MCL over many years could experience liver problems. Epichlorohydrin TT TT 0 Discharge from industrial chemical factories; An impurity of some water treatment chemicals Some people who drink water containing high levels of epichlorohydrin over a long period of time could experience stomach problems, and may have an increased risk of getting
cancer. Ethylene dibromide (ppt) .00005 1,000,000 50 0 Discharge from petroleum Some people who drink water containing ethylene 

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## refineries dibromide in excess of the MCL over many years could experience problems with their liver, stomach, reproductive system, or kidneys, and may have an increased risk of getting
cancer. Glyphosate (ppb) .7 1000 700 700 Runoff from herbicide use Some people who drink water containing glyphosate in excess of the MCL over many years could experience problems with their kidneys or reproductive difficulties. Heptachlor (ppt) .0004 1,000,000 400 0 Residue of banned pesticide Some people who drink water containing heptachlor in excess of the MCL over many years could experience liver damage and may have an increased risk of getting
cancer. Heptachlor epoxide (ppt) .0002 1,000,000 200 0 Breakdown of heptachlor Some people who drink water containing heptachlor epoxide in excess of the MCL over many years could experience liver damage, and may have an increased risk of getting
cancer. Hexachlorobenzene (ppb) .001 1000 1 0 Discharge from metal refineries and agricultural chemical factories Some people who drink water containing hexachlorobenzene in excess of the MCL over many years could experience problems with their liver or kidneys, or adverse reproductive effects, and may have an increased risk of getting
cancer. Hexachlorocyclopentadiene (ppb) .05 1000 50 50 Discharge from chemical factories Some people who drink water containing hexachlorocyclopentadiene well in excess of the MCL over many years could experience problems with their kidneys or stomach. Lindane (ppt) .0002 1,000,000 200 200 Runoff/leaching from insecticide used on cattle, lumber, gardens Some people who drink water containing lindane in excess of the MCL over many years could experience problems with their kidneys or liver. Methoxychlor (ppb) .04 1000 40 40 Runoff/leaching from insecticide used on fruits, vegetables, alfalfa, livestock Some people who drink water containing methoxychlor in excess of the MCL over many years could experience reproductive difficulties. Oxamyl [Vydate] (ppb) .2 1000 200 200 Runoff/leaching from insecticide used on apples, potatoes and tomatoes Some people who drink water containing oxamyl in excess of the MCL over many years could experience slight nervous system effects. PCBs [Polychlorinated biphenyls] (ppt) .0005 1,000,000 500 0 Runoff from landfills; Discharge of waste chemicals Some people who drink water containing PCBs in excess of the MCL over many years could experience changes in their skin, problems with their thymus gland, 

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## immune deficiencies, or reproductive or nervous system difficulties, and may have an increased risk of getting cancer. Pentachlorophenol (ppb) .001 1000 1 0 Discharge from wood preserving factories Some people who drink water containing pentachlorophenol in excess of the MCL over many years could experience problems with their liver or kidneys, and may have an increased risk of getting cancer. Picloram (ppb) .5 1000 500 500 Herbicide runoff Some people who drink water containing picloram in excess of the MCL over many years could experience problems with their liver. Simazine (ppb) .004 1000 4 4 Herbicide runoff Some people who drink water containing simazine in excess of the MCL over many years could experience problems with their blood. Toxaphene (ppb) .003 1000 3 0 Runoff/leaching from insecticide used on cotton and cattle Some people who drink water containing toxaphene in excess of the MCL over many years could have problems with their kidneys, liver, or thyroid, and may have an increased risk of getting
cancer. Volatile organic contaminants: Benzene (ppb) .005 1000 5 0 Discharge from factories; Leaching from gas storage tanks and landfills Some people who drink water containing benzene in excess of the MCL over many years could experience anemia or a decrease in blood platelets, and may have an increased risk of getting
cancer. Carbon tetrachloride (ppb) .005 1000 5 0 Discharge from chemical plants and other industrial activities Some people who drink water containing carbon tetrachloride in excess of the MCL over many years could experience problems with their liver and may have an increased risk of getting cancer. Chlorobenzene (ppb) .1 1000 100 100 Discharge from chemical and agricultural chemical factories Some people who drink water containing chlorobenzene in excess of the MCL over many years could experience problems with their liver or kidneys. o-Dichlorobenzene (ppb) .6 1000 600 600 Discharge from industrial chemical factories Some people who drinkwater containing odichlorobenzene well in excess of the MCL over many years could experience problems with their liver, kidneys, or circulatory systems. p-Dichlorobenzene (ppb) .075 1000 75 75 Discharge from industrial chemical factories Some people who drinkwater containing pdichlorobenzene in excess of the MCL over many years could experience anemia, damage to their liver, kidneys, or spleen, or changes in their blood. 

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## 1,2-Dichloroethane (ppb) .005 1000 5 0 Discharge from industrial chemical factories Some people who drink water containing 1,2- dichloroethane in excess of the MCL over many years may have an increased risk of getting cancer. 1,1-Dichloroethylene (ppb) .007 1000 7 7 Discharge from industrial chemical factories Some people who drink water containing 1,1- dichloroethylene in excess of the MCL over many years could experience problems with their liver. cis-1,2-Dichloroethylene (ppb) .07 1000 70 70 Discharge from industrial chemical factories Some people who drink water containing cis-1,2- dichloroethylene in excess of the MCL over many years could experience problems with their liver. trans-1,2-Dichloroethylene (ppb) .1 1000 100 100 Discharge from industrial chemical factories Some people who drink water containing trans-1,2- dichloroethylene well in excess of the MCL over many years could experience problems with their liver. Dichloromethane (ppb) .005 1000 5 0 Discharge from pharmaceutical and chemical factories Some people who drink water containing dichloromethane in excess of the MCL over many years could have liver problems and may have an increased risk of getting
cancer. 1,2-Dichloropropane (ppb) .005 1000 5 0 Discharge from industrial chemical factories Some people who drink water containing 1,2- dichloropropane in excess of the MCL over many years may have an increased risk of getting
cancer. Ethylbenzene (ppb) .7 1000 700 700 Discharge from petroleum refineries Some people who drink water containing ethylbenzene well in excess of the MCL over many years could experience problems with their liver or kidneys. Haloacetic Acids (HAA) (ppb) .060 1000 60 N/A By-product of drinking water disinfection Some people who drink water containing haloacetic acids in excess of the MCL over many years may have an increased risk of getting
cancer. Styrene (ppb) .1 1000 100 100 Discharge from rubber and plastic factories; Leaching from landfills Some people who drink water containing styrene well in excess of the MCL over many years could have problems with their liver, kidneys, or circulatory system. Tetrachloroethylene (ppb) .005 1000 5 0 Discharge from factories and dry cleaners Some people who drink water containing tetrachloroethylene in excess of the MCL over many years could have problems with their liver, and may have an increased risk of getting
cancer. 1,2,4-Trichlorobenzene (ppb) .07 1000 70 70 Discharge from textile-finishing factories Some people who drink water containing 1,2,4- trichlorobenzene well in excess of the MCL over many years could experience changes in 

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...1 These arsenic values are effective January 23, 2006. Until then, the MCL is 0.05 mg/L and there is no MCLG.

Key:

A L=Action Level

MCL=Maximum Contaminant Level

MCLG=Maximum Contaminant Level Goal

MFL=million fibers per liter

MRDL=Maximum Residual Disinfectant Level

MRDLG=Maximum Residual Disinfectant Level Goal

mrem/year=millirems per year (a m easure of radiation absorbed by the body)

N/A=Not Applicable 

## their adrenal glands. 1,1,1-Trichloroethane (ppb) .2 1000 200 200 Discharge from metal degreasing sites and other factories Some people who drink water containing 1,1,1- trichloroethane in excess of the MCL over many years could experience problems with their liver, nervous system, or circulatory system. 1,1,2-Trichloroethane (ppb) .005 1000 5 3 Discharge from industrial chemical factories Some people who drink water containing 1,1,2- trichloroethane well in excess of the MCL over many years could have problems with their liver, kidneys, or immune systems. Trichloroethylene (ppb) .005 1000 5 0 Discharge from metal degreasing sites and other factories Some people who drink water containing trichloroethylene in excess of the MCL over many years could experience problems with their liver and may have an increased risk of getting
cancer. TTHMs [Total trihalomethanes] (ppb) 0.10/.080 1000 100/80 N/A By-product of drinking water disinfection Some people who drink water containing trihalomethanes in excess of the MCL over many years may experience problems with their liver, kidneys, or central nervous systems, and may have an increased risk of getting
cancer. Toluene (ppm) 1 1 1 Discharge from petroleum factories Some people who drink water containing toluene well in excess of the MCL over many years could have problems with their nervous system, kidneys, or liver. Vinyl Chloride (ppb) .002 1000 2 0 Leaching from PVC piping; Discharge from plastics factories Some people who drink water containing vinyl chloride in excess of the MCL over many years may have an increased risk of getting cancer. Xylenes (ppm) 10 10 10 Discharge from petroleum factories; Discharge from chemical factories Some people who drink water containing xylenes in excess of the MCL over many years could experience damage to their nervous system. 

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...NTU=Nephelometric Turbidity Units (a measure of water clarity)
pCi/l=picocuries per liter (a measure of radioactivity)
ppm=parts per million, or milligrams per liter (mg/l)
ppb=parts per billion, or micrograms per liter (μg/l)

ppt=parts per trillion, or nanograms per liter

ppq=parts per quadrillion, or picograms per liter

TT=Treatment Technique

[65 FR 26024, May 4, 2000, as amended at 65 FR 76749, Dec. 7, 2000; 66 FR 7064, Jan. 22, 2001; 67 FR 70855, Nov. 27, 2002; 67 FR 73011, Dec. 9, 2002; 68 FR 14506, Mar. 25, 2003; 71 FR 65652, Nov. 8, 2006]


### Subpart P—Enhanced Filtration and Disinfection—Systems Serving 10,000 or More People

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### Source: 63 FR 69516, Dec. 16, 1998, unless otherwise noted.
§ 141.170 General requirements.

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(a) The requirements of this subpart P constitute national primary drinking water regulations. These regulations establish requirements for filtration and di sinfection that are in addition to criteria under which filtration and disinfection are required under subpartH of this part. The requirements of this subpart are applicable to subpart H systems serving at leas t 10,000 people, beginning January 1, 2002 unless otherwise specified in this subpart. The regulations in this subpart establish or extend treatment technique requirements in lieu of maximum contaminant levels for the following contaminants: Giardia lamblia, viruses, heterotrophic plate count bacteria, Legionella, Cryptosporidium, and turbidity. Each subpart H system serving at least 10,000 people mu st provide treatment of its source water that complies with these treatment technique requirements and are in addition to those identified in §141.70. The treatment technique requirements consist of installing and properly operating water treatment processes which reliably achieve:
(1) At least 99 percent (2-log) removal of Cryptosporidium between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer for filtered systems, or Cryptosporidium control under the watershed control plan for unfiltered systems.
(2) Compliance with the profiling and benchmark requirements under the provisions of §141.172.
(b) A public water system subject to the requirements of this subpart is considered to be in compliance with the requirements of paragraph (a) of this section if:
(1) It meets the requirements for avoiding filtrati on in §§141.71 and 141.171 and the disinfection requirements in §§141.72 and 141.172; or

(2) It meets the applicable filtration requirements in either §141.73 or §141.173 and the disinfection requirements in §§141.72 and 141.172.
(c) Systems are not permitted to begin construction of uncovered fi nished water storage facilities beginning February 16, 1999.
(d) Subpart H systems that did not conduct optio nal monitoring under §141.172 because they served fewer than 10,000 persons when such monitoring wa s required, but serve more than 10,000 persons prior to January 1, 2005 must comply with §§141.170, 141.171, 141.173, 141.174, and 141.175. These systems must also consult with the State to establis h a disinfection benchmark. A system that decides to make a significant change to its disinfection practi ce, as described in §141.172(c)(1)(i) through (iv) must consult with the State prior to making such change.

[63 FR 69516, Dec. 16, 1998, as amended at 66 FR 3779, Jan. 16, 2001; 67 FR 1836, Jan. 14, 2002; 69 FR 38856, June 29, 2004]


### § 141.171 Criteria for avoiding filtration.

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In addition to the requirements of §141.71, a public water system subject to the requirements of this subpart that does not provide filtration must meet a ll of the conditions of paragraphs (a) and (b) of this section.
(a) Site-specific conditions. In addition to site-specific conditions in §141.71(b), systems must maintain the watershed control program under §141.71(b)(2) to minimize the potential for contamination by Cryptosporidium oocysts in the source water. The watershed control program must, for Cryptosporidium :
(1) Identify watershed characteristics and activities which may have an adverse effect on source water quality; and
(2) Monitor the occurrence of activi ties which may have an adverse effect on source water quality.
(b) During the onsite inspection c onducted under the provisions of §141.71(b)(3), the State must 

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...determine whether the watershed control program establ ished under §141.71(b)(2) is adequate to limit potential contamination by Cryptosporidium oocysts. The adequacy of the program must be based on the comprehensiveness of the watershed review; th e effectiveness of the system's program to monitor and control detrimental activities occurring in the watershed; and the extent to which the water system has maximized land ownership and/or cont rolled land use within the watershed.


### § 141.172 Disinfection profiling and benchmarking.

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(a) Determination of systems required to profile. A public water system subject to the requirements of this subpart must determine its TTHM annual average using the procedure in paragraph (a)(1) of this section and its HAA5 annual average using the proce dure in paragraph (a)(2) of this section. The annual average is the arithmetic average of the quarterly av erages of four consecutive quarters of monitoring.

(1) The TTHM annual average must be the annual av erage during the same period as is used for the HAA5 annual average.
(i) Those systems that collected data under the provis ions of subpart M (Information Collection Rule) must use the results of the samples collected during the last four quarters of required monitoring under §141.142.
(ii) Those systems that use “grandfathered” HAA5 occurrence data that meet the provisions of paragraph (a)(2)(ii) of this section must use TTHM data collected at the same time under the provisions of §§141.12 and 141.30.
(iii) Those systems that use HAA5 occurrence data that meet the provisions of paragraph (a)(2)(iii)(A) of this section must use TTHM data collected at the same time under the provisions of §§141.12 and 141.30.
(2) The HAA5 annual average must be the annual average during the same period as is used for the TTHM annual average.
(i) Those systems that collected data under the provis ions of subpart M (Information Collection Rule) must use the results of the samples collected during the last four quarters of required monitoring under §141.142.

(ii) Those systems that have collected four quarters of HAA5 occurrence data that meets the routine monitoring sample number and location requirements for TTHM in §§141.12 and 141.30 and handling and analytical method requirem ents of §141.142(b)(1) may use those data to determine whether the requirements of this section apply.
(iii) Those systems that have not collected four quarters of HAA5 occurrence data that meets the provisions of either paragraph (a)(2)(i) or (i i) of this section by March 16, 1999 must either:
(A) Conduct monitoring for HAA5 that meets the routine monitoring sample number and location requirements for TTHM in §§141.12 and 141.30 and ha ndling and analytical method requirements of §141.142(b)(1) to determine the HAA5 annual average and whether the requirements of paragraph (b) of this section apply. This monitoring must be compl eted so that the applicability determination can be made no later than March 31, 2000, or
(B) Comply with all other provisions of this sect ion as if the HAA5 monitoring had been conducted and the results required compliance with paragraph (b) of this section.
(3) The system may request that the State approv e a more representative annual data set than the data set determined under paragraph (a)(1) or (2) of this section for the purpose of deter mining applicability of the requirements of this section.

(4) The State may require that a system use a mo re representative annual dat a set than the data set determined under paragraph (a)(1) or (2) of this se ction for the purpose of determining applicability of the requirements of this section.

(5) The system must submit data to the State on the sc hedule in paragraphs (a)(5)(i) through (v) of this section.
(i) Those systems that collected TTHM and HAA5 data under the provisions of subpart M (Information Collection Rule), as required by paragraphs (a)(1)(i) and (a)(2)(i) of this section, must submit the results of the samples collected during the last 12 months of required monitoring under §141.142 not later than December 31, 1999.
(ii) Those systems that have coll ected four consecutive quarters of HAA5 occurrence data that meets the routine monitoring sample number and location for TTHM in §§141.12 and 141.30 and handling and analytical method requirements of §141.142(b)(1), as a llowed by paragraphs (a)(1)(ii) and (a)(2)(ii) of this section, must submit those data to the State not later than April 16, 1999. Until the State has approved the data, the system must conduct monitori ng for HAA5 using the monitoring requirements specified under paragraph (a)(2)(iii) of this section.
(iii) Those systems that conduct monitoring for HAA5 using the monitoring requirements specified by paragraphs (a)(1)(iii) and (a)(2)(iii)(A) of this section, must submit TTHM and HAA5 data not later than March 31, 2000.
(iv) Those systems that elect to comp ly with all other provisions of this se ction as if the HAA5 monitoring had been conducted and the results required compliance with this section, as allowed under paragraphs (a)(2)(iii)(B) of this section, must notify the State in writing of their election not later than December 31, 1999.
(v) If the system elects to request that the State approv e a more representative annual data set than the data set determined under par agraph (a)(2)(i) of this section, the sys tem must submit this request in writing not later than December 31, 1999.
(6) Any system having either a TTHM annual average ≥ 0.064 mg/L or an HAA5 annual average ≥ 0.048 mg/L during the period identified in paragraphs (a)(1) and (2) of this section must comply with paragraph (b) of this section. 

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...(b) Disinfection profiling. (1) Any system that meets the criteria in paragraph (a)(6) of this section must develop a disinfection profile of its disinfection practice for a period of up to three years.

(2) The system must monitor daily for a period of 12 consecutive calendar mo nths to determine the total logs of inactivation for each day of operation, based on the CT99.9 values in Tables 1.1–1.6, 2.1, and 3.1 of §141.74(b), as appropriate, through the entire treatment plant. This system must begin this monitoring not later than April 1, 2000. As a minimu m, the system with a single point of disinfectant application prior to entrance to the distribution system must conduct the monitoring in paragraphs (b)(2) (i) through (iv) of this section. A system with more than one point of disinfectant application must conduct the monitoring in paragraphs (b)(2)(i) through (iv) of this section for each disinfection segment. The system must monitor the parameters necessary to determi ne the total inactivation ratio, using analytical methods in §141.74(a), as follows:
(i) The temperature of the disinfected water must be measured once per day at each residual disinfectant concentration sampling poi nt during peak hourly flow.

(ii) If the system uses chlorine, the pH of the di sinfected water must be measured once per day at each chlorine residual disinfectant concentration sampling point during peak hourly flow.
(iii) The disinfectant contact time (s) (“T”) must be determined for each day during peak hourly flow.
(iv) The residual disinfectant concentr ation(s) (“C”) of the water before or at the first customer and prior to each additional point of disinfection must be measured each day du ring peak hourly flow.

(3) In lieu of the monitoring conducted under the provis ions of paragraph (b)(2) of this section to develop the disinfection profile, the system may elect to meet the requirements of paragraph (b)(3)(i) of this section. In addition to the monitoring conducted unde r the provisions of paragraph (b)(2) of this section to develop the disinfection profile, the system may elect to meet the re quirements of paragraph (b)(3)(ii) of this section.

(i) A PWS that has three years of existing operational data may submit those data, a profile generated using those data, and a request that the State approv e use of those data in lieu of monitoring under the provisions of paragraph (b)(2) of this section not later than March 31, 2000. The State must determine whether these operational data are substantially equivalent to data collected under the provisions of paragraph (b)(2) of this section. These data must also be representative of Giardia lamblia inactivation through the entire treatment plant and not just of certain treatment segments. Until the State approves this request, the system is required to conduct monitoring under the provisio ns of paragraph (b)(2) of this section.
(ii) In addition to the disinfection profile generated under paragraph (b)(2) of this section, a PWS that has existing operational data may use those data to develop a disinfection profile for additional years. Such systems may use these additional yearly disinfection profiles to develop a benchmark under the provisions of paragraph (c) of this section. The State must determine whether these operational data are substantially equivalent to data collected under the provisions of paragraph (b)(2) of this section. These data must also be representative of inactivation through the entire tre atment plant and not just of certain treatment segments.
(4) The system must calculate the total inactivation ratio as follows:

(i) If the system uses only one po int of disinfectant application, th e system may determine the total inactivation ratio for the disinfection segment based on either of the m ethods in paragraph (b)(4)(i)(A) or (b)(4)(i)(B) of this section.

(A) Determine one inacti vation ratio (CTcalc/CT 99.9 ) before or at the first customer during peak hourly flow.
(B) Determine successive CTcalc/CT 99.9 values, representing sequential inactivation ratios, between the point of disinfectant application and a point before or at th e first customer during pe ak hourly flow. Under this alternative, the system must calculate the total inactivation ratio by determining (CTcalc/CT 99.9 ) for each sequence and then adding the (CTcalc/CT 99.9 ) values together to determine ( Σ (CTcalc/CT 99.9 )).

(ii) If the system uses more than one point of disi nfectant application before the first customer, the system must determine the CT value of each disinfecti on segment immediately prior to the next point of disinfectant application, or for the final segment, before or at the first customer, du ring peak hourly flow. The (CTcalc/CT 99.9 ) value of each segment and ( Σ (CTcalc/CT 99.9 )) must be calculated using the method in paragraph (b)(4)(i) of this section.
(iii) The system must determine the total logs of i nactivation by multiplying the value calculated in paragraph (b)(4)(i) or (ii) of this section by 3.0.

(5) A system that uses either chloramines or ozone for primary disinfection must also calculate the logs of inactivation for viruses using a method approved by the State.
(6) The system must retain disinfection profile data in graphic form, as a spreadsheet, or in some other format acceptable to the State for review as part of sanitary surveys conducted by the State.
(c) Disinfection benchmarking. (1) Any system required to develop a disinfection profile under the provisions of paragraphs (a) and (b) of this section and that decides to make a significant change to its disinfection practice must consult with the State prior to making such change. Significant changes to disinfection practice are:
(i) Changes to the point of disinfection;

(ii) Changes to the disinfectant( s) used in the treatment plant;
(iii) Changes to the disinfection process; and
(iv) Any other modification identified by the State.
(2) Any system that is modifying its disinfection practi ce must calculate its disinfection benchmark using the procedure specified in paragraphs (c)(2)(i) through (ii) of this section. 

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...(i) For each year of profiling data collected a nd calculated under paragraph (b) of this section, the system must determine the lowest average monthly Giardia lamblia inactivation in each year of profiling data. The system must determine the average Giardia lamblia inactivation for each calendar month for each year of profiling data by dividing the sum of daily Giardia lamblia of inactivation by the number of values calculated for that month.

(ii) The disinfection benchmark is the lowest mont hly average value (for systems with one year of profiling data) or average of lowest monthly average values (for systems with more than one year of profiling data) of the monthly logs of Giardia lamblia inactivation in each year of profiling data.

(3) A system that uses either chloramines or ozone for primary disinfection must also calculate the disinfection benchmark for viruses usin g a method approved by the State.
(4) The system must submit information in paragraphs (c )(4)(i) through (iii) of this section to the State as part of its consultation process.
(i) A description of the proposed change;

(ii) The disinfection profile for Giardia lamblia (and, if necessary, viruses) under paragraph (b) of this section and benchmark as required by paragraph (c)(2) of this section; and

(iii) An analysis of how the proposed change will affect the current levels of disinfection.

[63 FR 69516, Dec. 16, 1998, as amended at 66 FR 3779, Jan. 16, 2001]


### § 141.173 Filtration.

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Apublic water system subject to the requirements of th is subpart that does not meet all of the criteria in this subpart and subpart H of this part for avoiding fi ltration must provide treatment consisting of both disinfection, as specified in §141.72(b), and filtrati on treatment which complies with the requirements of paragraph (a) or (b) of this section or §141.73 (b) or (c) by December 31, 2001.
(a) Conventional filtration treatment or direct filtration. (1) For systems using conv entional filtration or direct filtration, the turbidity level of representative samples of a system's filtered water must be less than or equal to 0.3 NTU in at least 95 percent of the measurements taken each month, measured as specified in §141.74(a) and (c).

(2) The turbidity level of representative samples of a system's filtered water must at no time exceed 1 NTU, measured as specified in §141.74(a) and (c).

(3) A system that uses lime softening may acidify re presentative samples prior to analysis using a protocol approved by the State.
(b) Filtration technologies oth er than conventional filtration treatment, di rect filtration, slow sand filtration, or diatomaceous earth filtration. A public water system may use a filtration technology not listed in paragraph (a) of this section or in §141.73(b) or (c ) if it demonstrates to t he State, using pilot plant studies or other means, that the alternative filt ration technology, in comb ination with disinfection treatment that meets the requirements of §141.72(b) , consistently achieves 99.9 percent removal and/or inactivation of Giardia lamblia cysts and 99.99 percent removal and/or i nactivation of viruses, and 99 percent removal of Cryptosporidium oocysts, and the State approves the use of the filtration technology. For each approval, the State will set turbidity performance requirements that the system must meet at least 95 percent of the time and that the system may not exceed at any time at a level that consistently achieves 99.9 percent removal and/or inactivation of Giardia lamblia cysts, 99.99 percent removal and/or inactivation of viruses, and 99 percent removal of Cryptosporidium oocysts.

[63 FR 69516, Dec. 16, 1998, as amended at 65 FR 20313, Apr. 14, 2000; 66 FR 3779, Jan. 16, 2001]


### § 141.174 Filtration sampling requirements.

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(a) Monitoring requirements for syste ms using filtration treatment. In addi tion to monitoring required by §141.74, a public water system subject to the requirements of this subpart that provides conventional filtration treatment or direct filtration must conductcontinuous monitoring of turbidi ty for each individual filter using an approved method in §141.74(a) and must calibrate turbidimeters using the procedure specified by the manufacturer. Systems must record the results of individual filter monitoring every 15 minutes.
(b) If there is a failure in the continuous turbidity monitoring equipment, the system must conduct grab sampling every four hours in lieu of continuous mo nitoring, but for no more than five working days following the failure of the equipment.


### § 141.175 Reporting and recordkeeping requirements.

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In addition to the reporting and recordkeeping requirem ents in §141.75, a public water system subject to the requirements of this subpart that provides conventional filtration tr eatment or direct filtration must report monthly to the State the information specified in paragraphs (a) and (b) of this section beginning January 1, 2002. In addition to the reporting and recordkeeping requirements in §141.75, a public water system subject to the requirements of this subpart that provides filtration approved under §141.173(b) must report monthly to the State the information specified in paragraph (a) of this section beginning January 1, 2002. The reporting in paragraph (a) of this section is in lieu of the reporting specified in §141.75(b)(1).

(a) Turbidity measurements as required by §141.173 must be reported within 10 days after the end of each month the system serves water to the publ ic. Information that must be reported includes:
(1) The total number of filtered water tur bidity measurements taken during the month. 

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...(2) The number and percentage of filtered water tur bidity measurements taken during the month which are less than or equal to the turbidity limits specified in §141.173(a) or (b).

(3) The date and value of any turbidity measureme nts taken during the month which exceed 1 NTU for systems using conventional filtrati on treatment or direct filtration, or which exceed the maximum level set by the State under §141.173(b).
(b) Systems must maintain the results of individual filter monitoring taken under §141.174 for at least three years. Systems must report that they have cond ucted individual filter turbidity monitoring under §141.174 within 10 days after the end of each month the system serves water to the public. Systems must report individual filter turbidity measurement results taken under §141.174 within 10 days after the end of each month the system serves water to the public only if measurements demonstrate one or more of the conditions in paragr aphs (b)(1) through (4) of this section. Systems that use lime softening may apply to the State for alternative exceedance leve ls for the levels specifi ed in paragraphs (b)(1) through (4) of this section if they can demonstrate that hi gher turbidity levels in individual filters are due to lime carryover only and not due to degraded filter performance.

(1) For any individual filter that has a measured turbidity level of greater than 1.0 NTU in two consecutive measurements taken 15 minutes apart, the system must report the filter number, the turbidity measurement, and the date(s) on which the exceedance occurred. In addition, the system must either produce a filter profile for the filter within 7 days of the exceedance (if the system is not able to identify an obvious reason for the abnormal filter performanc e) and report that the profile has been produced or report the obvious reason for the exceedance.

(2) For any individual filter that has a measured turbidity level of greater than 0.5 NTU in two consecutive measurements taken 15 minutes apart at the end of the first four hours of c ontinuous filter operation after the filter has been backwashed or otherwise taken offline, the system must report the filter number, the turbidity, and the da te(s) on which the exceedance occurred. In addition, the system must either produce a filter profile for the filter within 7 days of the exceedance (if the system is not able to identify an obvious reason for the abnormal filter performanc e) and report that the profile has been produced or report the obvious reason for the exceedance.
(3) For any individual filter that has a measured turbidity level of greater than 1.0 NTU in two consecutive measurements taken 15 minutes apart at any time in each of three consecutive months, the system must report the filter number, the turbidity meas urement, and the date(s) on which the exceedance occurred. In addition, the system must conduct a self-assessment of the filter within 14 days of the exceedance and report that the self-assessment was conducted. The self assessment must consist of at least the following components: assessment of filterperformance; development of a filter profile; identification and prioritization of fa ctors limiting filter performance; assessment of the applicability of corrections; and preparation of a filter self-assessment report.
(4) For any individual filter that has a measured turbidity level of greater than 2.0 NTU in two consecutive measurements taken 15 minutes apart at any time in each of two consecutive months, the system must report the filter number, the turbidity measureme nt, and the date(s) on which the exceedance occurred. In addition, the system must arrange for the conduc t of a comprehensive performance evaluation by the State or a third party approved by the State no later than 30 days following the exceedance and have the evaluation completed and submitted to the State no later than 90 days following the exceedance.
(c) Additional reporting requirements. (1) If at any time the turbidity exceeds 1 NTU in representative samples of filtered water in a system using conventional filtration treatment or direct filtration, the system must inform the State as soon as possible, but no later than the end of the next business day.
(2) If at any time the turbidity in representative sa mples of filtered water exceeds the maximum level set by the State under §141.173(b) for filtration techn ologies other than conventional filtration treatment, direct filtration, slow sand filtration, or diatomaceo us earth filtration, the system must inform the State as soon as possible, but no later than the end of the next business day.

[63 FR 69516, Dec. 16, 1998, as amended at 66 FR 3779, Jan. 16, 2001]


### Subpart Q—Public Notification of Drinking Water Violations

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### Source: 65 FR 26035, May 4, 2000, unless otherwise noted.
§ 141.201 General public notification requirements.

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Public water systems in States with primacy for the public water system supervision (PWSS) program must comply with the requirements in this subpart no later than May 6, 2002 or on the date the Stateadopted rule becomes effective, whichever comes firs t. Public water systems in jurisdictions where EPA directly implements the PWSS program must comply with the requirements in this subpart on October 31, 2000. Prior to these dates, public water systems mu st continue to comply with the public notice requirements in §141.32 of this part. The term “primacy agency” is used in this subpart to refer to either EPA or the State or the Tribe in cases where EPA, the State, or the Tribe exercises primary enforcement responsibility for this subpart.
(a) Who must give public notice? Each owner or operator of a public water system (community water systems, non-transient non-communi ty water systems, and transient non-community water systems) must give notice for all violations of national primary drinking water regulations (NPDWR) and for other situations, as listed in Table 1. The term “NPDWR violations” is used in this subpart to include violations of the maximum contaminant level (MCL), maximum residual disinfection level (MRDL), treatment technique (TT), monitoring requirements , and testing procedures in thi s part 141. Appendix A to this subpart identifies the tier assignment for each specific violation or si tuation requiring a public notice.
Table 1 to §141.201—Violation Categories and Other Situations Requiring a Public Notice



## (1) NPDWR violations: (i) Failure to comply with an app licable maximum contaminant level (MCL) or maximum residual disinfectant level (MRDL). 

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...(b) What type of public notice is requ ired for each violation or situation? Public notice requirements are divided into three tiers, to take into account the se riousness of the violation or situation and of any potential adverse health effects that may be involved. The public notice require ments for each violation or situation listed in Table 1 of this section are determined by the tier to which it is assigned. Table 2 of this section provides the definition of each tier. Appendix A of this part identifies the tier assignment for each specific violation or situation.

Table 2 to §141.201—Definition of Public Notice Tiers

(c) Who must be notified? (1) Each public water system must provi de public notice to persons served by the water system, in accordance with this subpart. Pu blic water systems that sell or otherwise provide drinking water to other public water systems ( i.e. , to consecutive systems) ar e required to give public notice to the owner or operator of the consecutive system; the consecutive syst em is responsible for providing public notice to the persons it serves.
(2) If a public water system has a violation in a port ion of the distribution system that is physically or hydraulically isolated from other parts of the distribution system, the primacy agency may allow the system to limit distribution of the pub lic notice to only persons served by that portion of the system which is out of compliance. Permission by the primacy agency for limiting distribution of the notice must be granted in writing.
(3) A copy of the notice must also be sent to the prim acy agency, in accordance with the requirements under §141.31(d).


### § 141.202 Tier 1 Public Notice —Form, manner, and frequency of notice.

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(a) Which violations or situations re quire a Tier 1 public notice? Table 1 of this section lists the violation categories and other situations requiring a Tier 1 pub lic notice. Appendix A to this subpart identifies the tier assignment for each spec ific violation or situation.

Table 1 to §141.202—Violation Categories and Other Situations Requiring a Tier 1 Public Notice 

## (ii) Failure to comply with a prescribed treatment technique (TT). (iii) Failure to perform water quality monitoring, as required by the drinking water regulations. (iv) Failure to comply with testing procedures as prescribed by a drinking water regulation. (2) Variance and exemptions under sections 1415 and 1416 of SDWA: (i) Operation under a variance or an exemption. (ii) Failure to comply with the requirements of any schedule that has been set under a variance or exemption. (3) Special public notices: (i) Occurrence of a waterborne disease outbreak or other waterborne emergency. (ii) Exceedance of the nitrate MCL by non-community water systems (NCWS), where granted permission by the primacy agency under 141.11 (d) of this part. (iii) Exceedance of the secondary maximum contaminant level (SMCL) for fluoride. (iv) Availability of unregulated contaminant monitoring data. (v) Other violations and situations determined by the primacy agency to require a public notice under this subpart, not already listed in Appendix A.

(1) Tier 1 public notice—required for NPDWR violations and situations with significant potential to have serious adverse effects on human health as a result of short-term exposure. (2) Tier 2 public notice—required for all other NPDWR violations and situations with potential to have serious adverse effects on human health. (3) Tier 3 public notice—required for all other NPDWR violations and situations not included in Tier 1 and Tier 2.

(1) Violation of the MCL for total coliforms when fecal coliform or E. coli are present in the water distribution system (as specified in §141.63(b)), or when the water system fails to test for fecal coliforms or E. coli when any repeat sample tests positive for coliform (as specified in §141.21(e)); (2) Violation of the MCL for nitrate, nitrite, or total nitrate and nitrite, as defined in §141.62, or when the water system fails to take a confirmation sample within 24 hours of the system's receipt of the first sample showing an exceedance of the nitrate or nitrite MCL, as specified in §141.23(f)(2); (3) Exceedance of the nitrate MCL by non-community water systems, where permitted to exceed the MCL by the primacy agency under §141.11(d), as required under §141.209; (4) Violation of the MRDL for chlorine dioxide, as defined in §141.65(a), when 

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...(b) When is the Tier 1 public notice to be provided? What additional steps are required? Public water systems must:
(1) Provide a public notice as soon as practical but no later than 24 hours after the system learns of the violation;
(2) Initiate consultation with the primacy agency as soon as practi cal, but no later than 24 hours after the public water system learns of the violation or situation, to determine additional public notice requirements; and
(3) Comply with any additional public notification re quirements (including any r epeat notices or direction on the duration of the posted notices) that are estab lished as a result of the consultation with the primacy agency. Such requirements may include the timing, form, manner, frequency, and content of repeat notices (if any) and other actions designed to reach all persons served.
(c) What is the form and manner of the public notice? Public water systems must provide the notice within 24 hours in a form and manner reasonably ca lculated to reach all persons served. The form and manner used by the public water sys tem are to fit the specific situation, but must be designed to reach residential, transient, and non-trans ient users of the water system. In order to reach all persons served, water systems are to use, at a minimum, one or more of the following forms of delivery:

(1) Appropriate broadcast media (suc h as radio and television);
(2) Posting of the notice in conspicuous locati ons throughout the area served by the water system;
(3) Hand delivery of the notice to persons served by the water system; or
(4) Another delivery method approved in writing by the primacy agency.

[65 FR 26035, May 4, 2000, as amended at 67 FR 1836, Jan. 14, 2002; 71 FR 65652, Nov. 8, 2006]


### § 141.203 Tier 2 Public Notice —Form, manner, and frequency of notice.

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(a) Which violations or situations re quire a Tier 2 public notice? Table 1 of this section lists the violation categories and other situations requiring a Tier 2 pub lic notice. Appendix A to this subpart identifies the tier assignment for each spec ific violation or situation.
Table 1 to §141.203—Violation Categories and Other Situations Requiring a Tier 2 Public Notice 

## one or more samples taken in the distribution system the day following an exceedance of the MRDL at the entrance of the distribution system exceed the MRDL, or when the water system does not take the required samples in the distribution system, as specified in §141.133(c)(2)(i); (5) Violation of the turbidity MCL under §141.13(b), where the primacy agency determines after consultation that a Tier 1 notice is required or where consultation does not take place within 24 hours after the system learns of the violation; (6) Violation of the Surface Water Treatment Rule (SWTR), Interim Enhanced Surface Water Treatment Rule (IESWTR) or Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR) treatment technique requirement resulting from a single exceedance of the maximum allowable turbidity limit (as identified in appendix A), where the primacy agency determines after consultation that a Tier 1 notice is required or where consultation does not take place within 24 hours after the system learns of the violation; (7) Occurrence of a waterborne disease outbreak, as defined in §141.2, or other waterborne emergency (such as a failure or significant interruption in key water treatment processes, a natural disaster that disrupts the water supply or distribution system, or a chemical spill or unexpected loading of possible pathogens into the source water that significantly increases the potential for drinking water contamination); (8) Detection of E. coli , enterococci, or coliphage in source water samples as specified in §141.402(a) and §141.402(b); (9) Other violations or situations with significant potential to have serious adverse effects on human health as a result of short-term exposure, asdetermined by the primacy agency either in its regulations or on a case-bycase basis.

(1) All violations of the MCL, MRDL, and treatment technique requirements, except where a Tier 1 notice is required under §141.202(a) or where the primacy agency determines that a Tier 1 notice is required; (2) Violations of the monitoring and testing procedure requirements, where the primacy agency determines that a Tier 2 rather than a Tier 3 public notice is required, taking into account potential health impacts and persistence of the violation; and (3) Failure to comply with the terms and conditions of any variance or exemption in place. (4) Failure to take corrective action or failure to maintain at least 4-log 

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...(b) When is the Tier 2 public notice to be provided? (1) Public water systems must provide the public notice as soon as practical, but no later than 30 days after the system learns of the violation. If the public notice is posted, the notice must remain in place for as long as the violation or situation persists, but in no case for less than seven days, even if the violati on or situation is resolved. The primacy agency may, in appropriate circumstances, allow additional time for the initial notice of up to three months from the date the system learns of the violation. It is not appropriate for the primacy agency to grant an extension to the 30-day deadline for any unresolved violation or to allow across-the-board extensions by rule or policy for other violations or situations requiring a Tier 2 public notice. Extensions granted by the primacy agency must be in writing.
(2) The public water system must repeat the notice every three months as long as the violation or situation persists, unless the primacy agency determines that appropriate circumstances warrant a different repeat notice frequency. In no circumstance may the repeat notice be given less frequently than once per year. It is not appropriate for the primacy agency to allow less frequent repeat notice for an MCL violation under the Total Coliform Rule or a tre atment technique violation under the Surface Water Treatment Rule or Interim Enhanced Surface Water Treatment Rule. It is also not appropriate for the primacy agency to allow through its rules or polic ies across-the-board reductions in the repeat notice frequency for other ongoing violations requiring a Tier 2 repeat notice. Primacy agency determinations allowing repeat notices to be given less frequently than once every three months must be in writing.
(3) For the turbidity violations specified in this paragraph, public water systems must consult with the primacy agency as soon as practical but no later tha n 24 hours after the public water system learns of the violation, to determine whether a Tier 1 publicnotice under §141.202(a) is required to protect public health. When consultation does no t take place within the 24-hour period, the water system must distribute a Tier 1 notice of the vi olation within the next 24 hours ( i.e., no later than 48 hours after the system learns of the violation), following the requ irements under §141.202(b) an d (c). Consultation with the primacy agency is required for:
(i) Violation of the turbidity MCL under §141.13(b); or

(ii) Violation of the SWTR, IESWTR or LT1ESWTRtreatment technique requirement resulting from a single exceedance of the maximum allowable turbidity limit.

(c) What is the form and manner of the Tier 2 public notice? Public water systems must provide the initial public notice and any repeat notices in a form and manner that is reasonably calculated to reach persons served in the required time period. The form and manner of the public notice may vary based on the specific situation and type of water system, but it must at a minimum meet the following requirements:
(1) Unless directed otherwise by the primacy agency in writing, community water systems must provide notice by:
(i) Mail or other direct delivery to each customer receiving a bill and to other service connections to which water is delivered by the public water system; and
(ii) Any other method reasonably calculated to reach other persons regularly served by the system, if they would not normally be reached by the notice requ ired in paragraph (c)(1)(i) of this section. Such persons may include those who do not pay water bi lls or do not have service connection addresses (e.g., house renters, apartment dwellers, univers ity students, nursing home patients, prison inmates, etc.). Other methods may include: Publication in a local newspaper; delivery of multiple copies for distribution by customers that provide their drinking water to others (e.g., apartment building owners or large private employers); posting in public places served by the system or on the Internet; or delivery to community organizations.
(2) Unless directed otherwise by the primacy agency in writing, non-community water systems must provide notice by:
(i) Posting the notice in conspicuous locations thro ughout the distribution system frequented by persons served by the system, or by mail or direct delivery to each customer and service connection (where known); and

(ii) Any other method reasonably calculated to reach other persons served by the system if they would not normally be reached by the notice required in pa ragraph (c)(2)(i) of this se ction. Such persons may include those served who may not see a posted notice because the posted notice is not in a location they routinely pass by. Other methods may include: Publication in a local newspaper or newsletter distributed to customers; use of E-mail to notify employ ees or students; or, delivery of multiple copies in central locations (e.g., community centers).

[65 FR 26035, May 4, 2000, as amended at 67 FR 1836, Jan. 14, 2002; 71 FR 65652, Nov. 8, 2006]


### § 141.204 Tier 3 Public Notice —Form, manner, and frequency of notice.

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(a) Which violations or situations re quire a Tier 3 public notice? Table 1 of this section lists the violation categories and other situations requiring a Tier 3 pub lic notice. Appendix A to this subpart identifies the tier assignment for each spec ific violation or situation.
Table 1 to §141.204—Violation Categories and Other Situations Requiring a Tier 3 Public Notice 

## treatment of viruses (using inactivation, removal, or a State-approved combination of 4-log virus inactivation and removal) before or at the first customer under §141.403(a).

(1) Monitoring violations under 40 CFR part 141, except where a Tier 1 notice is required under §141.202(a) or where the primacy agency determines that a Tier 2 notice is required; (2) Failure to comply with a testing procedure established in 40 CFR part 141, except where a Tier 1 notice is required under §141.202(a)) or where the primacy agency determines that a Tier 2 notice is required; 

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...(b) When is the Tier 3 public notice to be provided? (1) Public water systems must provide the public notice not later than one year after the public water s ystem learns of the violation or situation or begins operating under a variance or exemption. Following the initial notice, the public water system must repeat the notice annually for as long as the violation, variance, exemption, or other situation persists. If the public notice is posted, the notice must remain in place for as long as the violation, variance, exemption, or other situation persists, but in no case less than seven days (even if the violation or situation is resolved).

(2) Instead of individual Tier 3 public notices, a publ ic water system may use an annual report detailing all violations and situations that occurred during the previous twelve months, as long as the timing requirements of paragraph (b)(1) of this section are met.
(c) What is the form and manner of the Tier 3 public notice? Public water systems must provide the initial notice and any repeat notices in a form and manner that is reasonably calculated to reach persons served in the required time period. The form and manner of the public notice may vary based on the specific situation and type of water system, but it must at a minimum meet the following requirements:
(1) Unless directed otherwise by the primacy agency in writing, community water systems must provide notice by:
(i) Mail or other direct delivery to each customer receiving a bill and to other service connections to which water is delivered by the public water system; and
(ii) Any other method reasonably calculated to reach other persons regularly served by the system, if they would not normally be reached by the notice requ ired in paragraph (c)(1)(i) of this section. Such persons may include those who do not pay water bi lls or do not have service connection addresses (e.g., house renters, apartment dwellers, univers ity students, nursing home patients, prison inmates, etc.). Other methods may include: Publication in a local newspaper; delivery of multiple copies for distribution by customers that provide their drinking water to others (e.g., apartment building owners or large private employers); posting in public plac es or on the Internet; or delivery to community organizations.
(2) Unless directed otherwise by the primacy agency in writing, non-community water systems must provide notice by:
(i) Posting the notice in conspicuous locations thro ughout the distribution system frequented by persons served by the system, or by mail or direct delivery to each customer and service connection (where known); and

(ii) Any other method reasonably calculated to reach other persons served by the system, if they would not normally be reached by the notice required in pa ragraph (c)(2)(i) of this se ction. Such persons may include those who may not see a posted notice becaus e the notice is not in a location they routinely pass by. Other methods may include: Publication in a local newspaper or newsletter distributed to customers; use of E-mail to notify employees or s tudents; or, delivery of multiple copies in central locations (e.g., community centers).

(d) In what situations may the Consumer Confidence Report be used to meet the Tier 3 public notice requirements? For community water systems, the Consum er Confidence Report (CCR) required under Subpart O of this part may be used as a vehicle for the initial Tier 3 public notice and all required repeat notices, as long as:
(1) The CCR is provided to persons served no later than 12 months after the system learns of the violation or situation as required under §141.204(b);
(2) The Tier 3 notice contained in the CCR fo llows the content requirements under §141.205; and
(3) The CCR is distributed following the delivery requirements under §141.204(c).

[65 FR 26035, May 4, 2000; 65 FR 38629, June 21, 2000]


### § 141.205 Content of the public notice.

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(a) What elements must be included in the public notice for violations of National Primary Drinking Water Regulations (NPDWR) or other situations requiring a public notice? When a public water system violates a NPDWR or has a situation requiring public notifi cation, each public notice must include the following elements:
(1) A description of the violation or situation, includ ing the contaminant(s) of concern, and (as applicable) the contaminant level(s);
(2) When the violation or situation occurred;
(3) Any potential adverse health effects from the violation or situation, includ ing the standard language under paragraph (d)(1) or (d)(2) of this section, whichever is applicable;

(4) The population at risk, including subpopulations pa rticularly vulnerable if exposed to the contaminant in their drinking water;
(5) Whether alternative water supplies should be used; 

## (3) Operation under a variance granted under Section 1415 or an exemption granted under Section 1416 of the Safe Drinking Water Act; (4) Availability of unregulated contamin ant monitoring resu lts, as required under §141.207; and (5) Exceedance of the fluoride secondary maximum contaminant level (SMCL), as required under §141.208. 

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...(6) What actions consumers should take, including when they should seek medical help, if known;
(7) What the system is doing to correct the violation or situation;
(8) When the water system expects to retur n to compliance or resolve the situation;
(9) The name, business address, and phone number of the water system owner, operator, or designee of the public water system as a source of addi tional information conc erning the notice; and
(10) A statement to encourage the notice recipient to di stribute the public notice to other persons served, using the standard language under paragraph (d)(3) of this section, where applicable.
(b) What elements must be included in the public notice for public water systems operating under a variance or exemption? (1) If a public water system has been granted a variance or an exemption, the public notice must contain:
(i) An explanation of the reasons for the variance or exemption;
(ii) The date on which the variance or exemption was issued;

(iii) A brief status report on the steps the system is taking to install treatment, fi nd alternative sources of water, or otherwise comply with the terms and schedules of the variance or exemption; and
(iv) A notice of any opportunity for public input in the review of the variance or exemption.
(2) If a public water system viol ates the conditions of a va riance or exemption, the public notice must contain the ten elements listed in paragraph (a) of this section.

(c) How is the public notice to be presented? (1) Each public notice required by this section:
(i) Must be displayed in a conspicuous way when printed or posted;
(ii) Must not contain overly technica l language or very small print;
(iii) Must not be formatted in a way that defeats the purpose of the notice;
(iv) Must not contain language which nullifies the purpose of the notice.
(2) Each public notice required by this section must comply with multilingual requirements, as follows:
(i) For public water systems serving a large proportion of non-English speaking consumers, as determined by the primacy agency, the public notice must contain information in the appropriate language(s) regarding the importance of the notice or contain a telephone number or address where persons served may contact the water system to obtain a translated copy of the notice or to request assistance in the appropriate language.
(ii) In cases where the primacy agency has not de termined what constitutes a large proportion of nonEnglish speaking consumers, the public water system must include in the public notice the same information as in paragraph (c)(2)(i) of this secti on, where appropriate to reach a large proportion of nonEnglish speaking persons served by the water system.
(d) What standard language must public water systems include in their public notice? Public water systems are required to include the following standard language in their public notice:
(1) Standard health effects language for MCL or MRDL violations, treatment technique violations, and violations of the condition of a variance or exemption. Public water systems must include in each public notice the health effects language specified in ap pendix B to this subpart corresponding to each MCL, MRDL, and treatment technique violation listed in ap pendix A to this subpart, and for each violation of a condition of a variance or exemption.
(2) Standard language for monitoring and testing pr ocedure violations. Public water systems must include the following language in their notice, including the language necessary to fill in the blanks, for all monitoring and testing procedure violati ons listed in appendix A to this subpart:


### We are required to monitor your drinking water for specific contaminants on a regular basis. Results of regular monitoring are an indicator of whether or not your drinking water meets health standards. During [compliance period], we “did not monitor or test” or “did not complete all monitoring or testing” for [contaminant(s)], and therefore cannot be sure of the quality of your drinking water during that time.

(3) Standard language to encourage the distribution of the public notice to all persons served. Public water systems must include in their notice the following language (where applicable):


### Please share this information with all the other people who drink this water, especially those who may not have received this notice directly (for example, people in apartments, nursing homes, schools, and businesses). You can do this by posting this notice in a public place or distributing copies by hand or mail.
§ 141.206 Notice to new billing units or new customers.

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(a) What is the requirement for community water systems? Community water systems must give a copy of the most recent public notice for any continuing vi olation, the existence of a va riance or exemption, or other ongoing situations requiring a public notice to a ll new billing units or new customers prior to or at the time service begins.
(b) What is the requirement for non-community water systems? Non-community water systems must continuously post the public notice in conspicuous locations in order to inform new consumers of any continuing violation, variance or exemption, or other si tuation requiring a public notice for as long as the 

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...violation, variance, exemption, or other situation persists.


### § 141.207 Special notice of the availability of unregulated contaminant monitoring results.

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(a) When is the special notice to be given? The owner or operator of a community water system or nontransient, non-community water system required to m onitor under §141.40 must notify persons served by the system of the availability of the results of such sampling no later than 12 months after the monitoring results are known.
(b) What is the form and manner of the special notice? The form and manner of the public notice must follow the requirements for a Tier 3 public notice prescribed in §§141.204(c), (d)(1), and (d)(3). The notice must also identify a person and provide the telephone number to contact for information on the monitoring results.


### § 141.208 Special notice for exceedance of the SMCL for fluoride.

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(a) When is the special notice to be given? Community water systems that exceed the fluoride secondary maximum contaminant level (SMCL) of 2 mg/l as specified in §143.3 (determined by the last single sample taken in accordance with §141.23), but do not exceed the maximum contaminant level (MCL) of 4 mg/l for fluoride (as specified in §141.62), must provide the public notice in paragraph (c) of this section to persons served. Public notice must be provided as soon as practical but no later than 12 months from the day the water system learns of the exceeda nce. A copy of the notice must also be sent to all new billing units and new customers at the time service begins and to the State public health officer. The public water system must repeat the notice at least annually for as long as the SMCL is exceeded. If the public notice is posted, the notice must remain in place for as long as the SMCL isexceeded, but in no case less than seven days (even if the exceedance is eliminated). On a case-bycase basis, the primacy agency may require an initial notice sooner than 12 months and repeat notices more frequently than annually.
(b) What is the form and manner of the special notice? The form and manner of the public notice (including repeat notices) must follow the requirem ents for a Tier 3 public notice in §141.204(c) and (d) (1) and (d)(3).

(c) What mandatory language must be contained in the special notice? The notice must contain the following language, including the language necessary to fill in the blanks:


### This is an alert about your drinking water and a cosmetic dental problem that might affect children under nine years of age. At low levels, fluoride can help prevent cavities, but children drinking water containing more than 2 milligrams per liter (mg/l) of fluoride may develop cosmetic discoloration of their permanent teeth (dental fluorosis). The drinking water provided by your community water system [ name ] has a fluoride concentration of [ insert value ] mg/l.
Dental fluorosis, in its moderate or severe forms, may result in a brown staining and/or pitting of the permanent teeth. This problem occurs only in developing teeth, before they erupt from the gums. Children under nine should be provided with alternative sources of drinking water or water that has been treated to remove the fluoride to avoid the possibility of staining and pitting of their permanent teeth. You may also want to contact your dentist about proper use by young children of fluoride-containing products. Older children and adults may safely drink the water.
Drinking water containing more than 4 mg/L of fluoride (the U.S. Environmental Protection Agency's drinking water standard) can increase your risk of developing bone disease. Your drinking water does not contain more than 4 mg/l of fluoride, but we're required to notify you when we discover that the fluoride levels in your drinking water exceed 2 mg/l because of this cosmetic dental problem.
For more information, please call [name of water system contact] of [name of community water system] at [phone number]. Some home water treatment units are also available to remove fluoride from drinking water. To learn more about available home water treatment units, you may call NSF International at 1–877–8–NSF–HELP.”
§ 141.209 Special notice for nitrate exceedances above MCL by non-community water systems (NCWS), where granted permission by the primacy agency under §141.11(d)

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(a) When is the special notice to be given? The owner or operator of a non-community water system granted permission by the primacy agency under §14 1.11(d) to exceed the nitrate MCL must provide notice to persons served according to the requireme nts for a Tier 1 notice under §141.202(a) and (b).
(b) What is the form and manner of the special notice? Non-community water systems granted permission by the primacy agency to exceed the ni trate MCL under §141.11(d) must provide continuous posting of the fact that nitrate levels exceed 10 mg/l and the potential health effects of exposure, according to the requirements for Tier 1 notice de livery under §141.202(c) and the content requirements under §141.205.


### § 141.210 Notice by primacy agency on behalf of the public water system.

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(a) May the primacy agency give the notice on behalf of the public water system? The primacy agency may give the notice required by this subpart on behalf of the owner and operator of the public water system if the primacy agency complies with the requirements of this subpart. 

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...(b) What is the responsibility of the public water systemwhen notice is given by the primacy agency? The owner or operator of the public water system re mains responsible for ensuring that the requirements of this subpart are met.


### § 141.211 Special notice for repeated failure to conduct monitoring of the source water for Cryptosporidium and for failure to determine bin classification or mean Cryptosporidium level.

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(a) When is the special notice for repeated failure to monitor to be given? The owner or operator of a community or non-community water system that is required to monitor source water under §141.701 must notify persons served by the water system that monitoring has no t been completed as specified no later than 30 days after the system has failed to colle ct any 3 months of monitor ing as specified in §141.701(c). The notice must be repeated as specified in §141.203(b).

(b) When is the special notice for failure to determine bin classification or mean Cryptosporidium level to be given? The owner or operator of a community or non-community water system that is required to determine a bin classification under §141.710, or to determine mean Cryptosporidium level under §141.712, must notify persons served by the water s ystem that the determination has not been made as required no later than 30 days after the system has failed report the determination as specified in §141.710(e) or §141.712(a), respectively. The notice must be repeated as specified in §141.203(b). The notice is not required if the system is complying wi th a State-approved schedule to address the violation.

(c) What is the form and manner of the special notice? The form and manner of the public notice must follow the requirements for a Tier 2 public notice pr escribed in §141.203(c). The public notice must be presented as required in §141.205(c).

(d) What mandatory language must be contained in the special notice? The notice must contain the following language, including the language necessary to fill in the blanks.
(1) The special notice for repeated failure to co nduct monitoring must contain the following language:


### We are required to monitor the source of your drinking water for Cryptosporidium. Results of the monitoring are to be used to determine whether water treatment at the (treatment plant name) is sufficient to adequately remove Cryptosporidium from your drinking water. We are required to complete this monitoring and make this determination by (required bin determination date). We “did not monitor or test” or “did not complete all monitoring or testing” on schedule and, therefore, we may not be able to determine by the required date what treatment modifications, if any, must be made to ensure adequate Cryptosporidium removal. Missing this deadline may, in turn, jeopardize our ability to have the required treatment modifications, if any, completed by the deadline required, (date).
For more information, please call (name of water system contact) of (name of water system) at (phone number).

(2) The special notice for failure to determine bin classification or mean Cryptosporidium level must contain the following language:


### We are required to monitor the source of your drinking water for Cryptosporidium in order to determine by (date) whether water treatment at the (treatment plant name) is sufficient to adequately remove Cryptosporidium from your drinking water. We have not made this determination by the required date. Our failure to do this may jeopardize our ability to have the required treatment modifications, if any, completed by the required deadline of (date). For more information, please call (name of water system contact) of (name of water system) at (phone number).

(3) Each special notice must also include a description of what the system is doing to correct the violation and when the system expects to return to compliance or resolve the situation.

[71 FR 768, Jan. 5, 2006]


### Appendix A to Subpart Q of Part 141—NPDWR Violations and Other Situations Requiring Public Notice 1

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## Contaminant MCL/MRDL/TT violations 2 

## Monitoring & testing procedure violations Tier of public notice required Citation Tier of public notice required Citation I. Violations of National Primary Drinking Water Regulations (NPDWR): 3 

## A. Microbiological Contaminants 1. Total coliform 2 141.63(a) 3 141.21 (a)–(e) 2. Fecal coliform/E. coli 1 141.63(b) 4 

## 1, 3 141.21 (e) 3. Turbidity MCL 2 141.13(a) 3 141.22 

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## 4. Turbidity MCL (average of 2 days' samples >5 NTU) 5 

## 2, 1 141.13(b) 3 141.22

5. Turbidity (for TT violations resulting from a single exceedance of maximum allowable turbidity level) 6 

## 2, 1 141.71(a)(2), 141.71(c)(2)(i),

141.73(a)(2), 141.73 (b)(2), 141.73 (c)(2), 141.73(d), 141.173(a)(2),

141.173(b), 141.551(b) 3 141.74 (a)(1), 141.74 (b)(2), 141.74 (c)(1), 141.174, 141.560 (a)–(c), 141.561. 6. Surface Water Treatment Rule violations, other than violations resulting from single exceedance of max. allowable turbidity level (TT) 2 141.70–141.73 3 141.74

7. Interim Enhanced Surface Water Treatment Rule violations, other than violations resulting from single exceedance of max. turbidity level (TT) 7 

## 2 141.170– 141.173, 141.500–

141.553 3 141.172, 141.174, 141.530– 141.544, 141.560– 141.564.

8. Filter Backwash Recycling Rule violations 2 141.76(c) 3 141.76 (b), (d)
9. Long Term 1 Enhanced Surface Water Treatment Rule violations 2 141.500– 141.553 3 141.530– 141.544, 141.560– 141.564. 10. LT2ESWTR violations 2 141.710– 141.720 22 

## 2, 3 141.701– 141.705 and 141.708– 141.709. 11. Ground Water Rule violations 2 141.404 3 141.402 (h), 141.403 (d). B. Inorganic Chemicals (IOCs) 1. Antimony 2 141.62(b) 3 141.23 (a), (c) 2. Arsenic 2 8 

## 141.62(b) 3 11 

## 141.23 (a), (c) 3. Asbestos (fibers >10 μm) 2 141.62(b) 3 141.23 (a)–(b) 4. Barium 2 141.62(b) 3 141.23 (a), (c) 5. Beryllium 2 141.62(b) 3 141.23 (a), (c) 6. Cadmium 2 141.62(b) 3 141.23 (a), (c) 7. Chromium (total) 2 141.62(b) 3 141.23 (a), (c) 8. Cyanide 2 141.62(b) 3 141.23 (a), (c) 9. Fluoride 2 141.62(b) 3 141.23 (a), (c) 10. Mercury (inorganic) 2 141.62(b) 3 141.23 (a), (c) 11. Nitrate 1 141.62(b) 12 

## 1, 3 141.23 (a), (d), 141.23(f) (2) 12. Nitrite 1 141.62(b) 12 

## 1, 3 141.23 (a), (e), 

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## 141.23(f) (2) 13. Total Nitrate and Nitrite 1 141.62(b) 3 141.23 (a) 14. Selenium 2 141.62(b) 3 141.23 (a), (c) 15. Thallium 2 141.62(b) 3 141.23 (a), (c) C. Lead and Copper Rule (Action Level for lead is 0.015 mg/L, for copper is 1.3 mg/L) 1. Lead and Copper Rule (TT) 2 141.80–141.85 3 141.86– 141.89 D. Synthetic Organic Chemicals (SOCs) 1. 2,4–D 2 141.61(c) 3 141.24 (h) 2. 2,4,5–TP (Silvex) 2 141.61(c) 3 141.24 (h) 3. Alachlor 2 141.61(c) 3 141.24 (h) 4. Atrazine 2 141.61(c) 3 141.24 (h) 5. Benzo(a)pyrene (PAHs) 2 141.61(c) 3 141.24 (h) 6. Carbofuran 2 141.61(c) 3 141.24 (h) 7. Chlordane 2 141.61(c) 3 141.24 (h) 8. Dalapon 2 141.61(c) 3 141.24 (h) 9. Di (2-ethylhexyl) adipate 2 141.61(c) 3 141.24 (h) 10. Di (2-ethylhexyl) phthalate 2 141.61(c) 3 141.24 (h) 11. Dibromochloropropane 2 141.61(c) 3 141.24 (h) 12. Dinoseb 2 141.61(c) 3 141.24 (h) 13. Dioxin (2,3,7,8- TCDD) 2 141.61(c) 3 141.24 (h) 14. Diquat 2 141.61(c) 3 141.24 (h) 15. Endothall 2 141.61(c) 3 141.24 (h) 16. Endrin 2 141.61(c) 3 141.24 (h) 17. Ethylene dibromide 2 141.61(c) 3 141.24 (h) 18. Glyphosate 2 141.61(c) 3 141.24 (h) 19. Heptachlor 2 141.61(c) 3 141.24 (h) 20. Heptachlor epoxide 2 141.61(c) 3 141.24 (h) 21. Hexachlorobenzene 2 141.61(c) 3 141.24 (h)22. Hexachlorocyclopentadiene 2 141.61(c) 3 141.24 (h) 23. Lindane 2 141.61(c) 3 141.24 (h) 24. Methoxychlor 2 141.61(c) 3 141.24 (h) 25. Oxamyl (Vydate) 2 141.61(c) 3 141.24 (h) 26. Pentachlorophenol 2 141.61(c) 3 141.24 (h) 27. Picloram 2 141.61(c) 3 141.24 (h) 

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## 28. Polychlorinated biphenyls (PCBs) 2 141.61(c) 3 141.24 (h) 29. Simazine 2 141.61(c) 3 141.24 (h) 30. Toxaphene 2 141.61(c) 3 141.24 (h) E. Volatile Organic Chemicals (VOCs) 1. Benzene 2 141.61(a) 3 141.24(f) 2. Carbon tetrachloride 2 141.61(a) 3 141.24(f) 3. Chlorobenzene (monochlorobenzene) 2 141.61(a) 3 141.24(f)
4. o-Dichlorobenzene 2 141.61(a) 3 141.24(f) 5. p-Dichlorobenzene 2 141.61(a) 3 141.24(f) 6. 1,2-Dichloroethane 2 141.61(a) 3 141.24(f) 7. 1,1- Dichloroethylene 2 141.61(a) 3 141.24(f)
8. cis-1,2- Dichloroethylene 2 141.61(a) 3 141.24(f)
9. trans-1,2- Dichloroethylene 2 141.61(a) 3 141.24(f)
10. Dichloromethane 2 141.61(a) 3 141.24(f) 11. 1,2- Dichloropropane 2 141.61(a) 3 141.24(f)
12. Ethylbenzene 2 141.61(a) 3 141.24(f) 13. Styrene 2 141.61(a) 3 141.24(f) 14. Tetrachloroethylene 2 141.61(a) 3 141.24(f)
15. Toluene 2 141.61(a) 3 141.24(f) 16. 1,2,4- Trichlorobenzene 2 141.61(a) 3 141.24(f)
17. 1,1,1- Trichloroethane 2 141.61(a) 3 141.24(f)
18. 1,1,2- Trichloroethane 2 141.61(a) 3 141.24(f)
19. Trichloroethylene 2 141.61(a) 3 141.24(f) 20. Vinyl chloride 2 141.61(a) 3 141.24(f) 21. Xylenes (total) 2 141.61(a) 3 141.24(f) F. Radioactive Contaminants 1. Beta/photon emitters 2 141.66(d) 3 141.25 (a) 141.26 (b) 2. Alpha emitters 2 141.66(c) 3 141.25 (a) 141.26 (a) 3. Combined radium (226 and 228) 2 141.66(b) 3 141.25 (a) 141.26 (a) 4. Uranium 9 

## 2 141.66(e) 10 

## 3 141.25 (a) 141.26 (a) G. Disinfection Byproducts (DBPs), Byproduct Precursors, Disinfectant Residuals. Where disinfection is used in the treatment of drinking water, disinfectants combine with organic and inorganic matter present in water to form chemicals called disinfection byproducts (DBPs). EPA sets standards for controlling the levels of disinfectants and DBPs in drinking water, including trihalomethanes (THMs) and haloacetic acids 

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## (HAAs). 13 

## 1. Total trihalomethanes (TTHMs) 2 14 

## 141.64(b) 3 141.132 (a)–(b), 141.600– 141.605, 141.620–

141.629 2. Haloacetic Acids (HAA5) 2 141.64(b) 3 141.132 (a)–(b), 141.600– 141.605, 141.620–

141.629 3. Bromate 2 141.64(a) 3 141.132 (a)–(b) 4. Chlorite 2 141.64(a) 3 141.132 (a)–(b) 5. Chlorine (MRDL) 2 141.65(a) 3 141.132 (a), (c) 6. Chloramine (MRDL) 2 141.65(a) 3 141.132 (a), (c) 7. Chlorine dioxide (MRDL), where any 2 consecutive daily samples at entrance to distribution system only are above MRDL 2 141.65(a), 141.133(c)(3) 2 15 

## , 3 141.132 (a), (c), 141.133

(c)(2)

8. Chlorine dioxide (MRDL), where sample(s) in distribution system the next day are also above MRDL 16 

## 1 141.65(a), 141.133(c)(3) 1 141.132 (a), (c), 141.133

(c)(2)

9. Control of DBP precursors—TOC (TT) 2 141.135(a)–(b) 3 141.132 (a), (d) 10. Bench marking and disinfection profiling N/A N/A 3 141.172 141.530– 141.544. 11. Development of monitoring plan N/A N/A 3 141.132 (f) H. Other Treatment Techniques 1. Acrylamide (TT) 2 141.111 N/A N/A 2. Epichlorohydrin (TT) 2 141.111 N/A N/A II. Unregulated Contaminant Monitoring: 17 

## A. Unregulated contaminants N/A N/A 3 141.40 B. Nickel N/A N/A 3 141.23 (c), (k) III. Public Notification for Variances and Exemptions: A. Operation under a variance or exemption 3 18 

## 1415, 1416, N/A N/A

B. Violation of conditions of a variance or exemption 2 1415, 1416, 19 

## 142.307 N/A N/A

IV. Other Situations Requiring Public Notification: A. Fluoride secondary maximum contaminant level (SMCL) exceedance 3 143.3 N/A N/A

B. Exceedance of nitrate MCL for non-community systems, as allowed by primacy agency 1 141.11(d) N/A N/A

C. Availability of unregulated contaminant monitoring data 3 141.40 N/A N/A

D. Waterborne disease outbreak 1 141.2, 141.71 (c)(2)(ii) N/A N/A

E. Other waterborne emergency 20 

## 1 N/A N/A N/A

F. Source Water Sample Positive for GWR Fecal 1 141.402(g) N/A N/A 

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...A ppendix A—Endnotes

1. Violations and other situations not listed in this tabl e (e.g., failure to prepare Consumer Confidence Reports), do not require notice, unless otherwise dete rmined by the primary agency. Primacy agencies may, at their option, also require a more stringent public notice tier (e.g., Tier 1 instead of Tier 2 or Tier 2 instead of Tier 3) for specific violations and situati ons listed in this Appendix, as authorized under §141.202(a) and §141.203(a).

2. MCL—Maximum contaminant level, MRDL—Maximum residual disinfectant level, TT—Treatment technique
3. The term Violations of National Primary Drinking Wa ter Regulations (NPDWR) is used here to include violations of MCL, MRDL, treatment technique, mo nitoring, and testing proc edure requirements.

4. Failure to test for fecal coliform or E. coli is a Tier 1 violation if tes ting is not done after any repeat sample tests positive for coliform. All other total coli form monitoring and testing procedure violations are Tier 3.
5. Systems that violate the turbidity MCL of 5 NTU based on an average of measurements over two consecutive days must consult with the primacy agen cy within 24 hours after learning of the violation. Based on this consultation, the primacy agency may subs equently decide to elevate the violation to Tier 1. If a system is unable to make contact with the primac y agency in the 24-hour period, the violation is automatically elevated to Tier 1.
6. Systems with treatment technique violations invo lving a single exceedance of a maximum turbidity limit under the Surface Water Treatment Rule (S WTR), the Interim Enhanced Surface Water Treatment Rule (IESWTR), or the Long Term 1 Enhance d Surface Water Treatment Rule (LT1ESWTR) are required to consult with the primacy agency within 24 hours after learning of the violation. Based on this consultation, the primacy agency may subsequently de cide to elevate the violation to Tier 1. If a system is unable to make contact with the primacy agency in the 24-hour period, the violation is automatically elevated to Tier 1.
7. Most of the requirements of the Interim Enhanced Surface Water Treatment Rule (63 FR 69477) (§§141.170–141.171, 141.173–141.174) become effective January 1, 2002 for Subpart H systems (surface water systems and ground water systems unde r the direct influence of surface water) serving at least 10,000 persons. However, §141.172 has some requirements that become effective as early as A pril 16, 1999. The Surface Water Treatment Rule re mains in effect for systems serving at least 10,000 persons even after 2002; the Interim Enhanced Surface Water Treatment Rule adds additional requirements and does not in many cases supercede the SWTR.

8. The arsenic MCL citations are effective January 23 , 2006. Until then, the citations are §141.11(b) and §141.23(n).

9. The uranium MCL Tier 2 violati on citations are effective December 8, 2003 for all community water systems.
10. The uranium Tier 3 violation citations are effective December 8, 2000 for all community water systems.

11. The arsenic Tier 3 violation MCL citations are effective January 23, 2006. Until then, the citations are §141.23(a), (l).

12. Failure to take a confirmation sample within 24 hou rs for nitrate or nitrite after an initial sample exceeds the MCL is a Tier 1 violation. Other mo nitoring violations for nitrate are Tier 3.
13. Subpart H community and non-transient non-community systems serving ≥ 10,000 must comply with new DBP MCLs, disinfectant MRDLs, and related moni toring requirements beginning January 1, 2002. A ll other community and non-transient non-community systems must meet the MCLs and MRDLs beginning January 1, 2004. Subpart H transient non-community systems serving 10,000 or more persons and using chlorine dioxide as a disinfectant or oxidant must comply with the chlorine dioxide MRDL beginning January 1, 2002. Subpart H transient non-community systems serving fewer than 10,000 persons and using only ground water not under the direct influence of surface water and using chlorine dioxide as a disinfectant or oxidant must comply with the chlorine dioxide MRDL beginning January 1, 2004.
14. §§141.64(b)(1) 141.132(a)–(b) apply until § §141.620–141.630 take effect under the schedule in §141.620(c).

15. Failure to monitor for chlori ne dioxide at the entrance to the distribution system the day after exceeding the MRDL at the entrance to the distribution system is a Tier 2 violation.
16. If any daily sample taken at the entrance to the distribution system exceeds the MRDL for chlorine dioxide and one or more samples taken in the distribution system the next day exceed the MRDL, Tier 1 notification is required. Failure to take the required samples in the distribution system after the MRDL is exceeded at the entry point also triggers Tier 1 notification.
17. Some water systems must monitor for certain unregulated contaminants listed in §141.40.
18. This citation refers to §§1415 and 1416 of the Safe Drinking Water Act. §§1415 and 1416 require that “a schedule prescribed. . . for a public water system granted a vari ance [or exemption] shall require compliance by the system. . .”
19. In addition to §§1415 and 1416 of the Safe Drinking Water Act, 40 CFR 142.307 specifies the items and schedule milestones that must be included in a variance for small systems.
20. Other waterborne emergencies require a Tier 1 public notice under §141.202(a) for situations that do not meet the definition of a waterborne disease outbreak given in 40 CFR 141.2 but that still have the 

## indicators: E. coli, enterococci, or coliphage G. Other situations as determined by primacy agency 21 

## 1, 2, 3 N/A N/A N/A 

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...potential to have serious adverse effects on health as a result of short-term exposure. These could include outbreaks not related to treatment deficiencies, as well as situations that have the potential to cause outbreaks, such as failures or significant interruption in water treatment processes, natural disasters that disrupt the water supply or distribution system, chemical spills, or unexpected loading of possible pathogens into the source water.

21. Primacy agencies may place other situations in an y tier they believe appropriate, based on threat to public health.

22. Failure to collect three or more samples for Cryptosporidium analysis is a Tier 2 violation requiring special notice as specified in §141.211. All other moni toring and testing procedure violations are Tier 3.

[65 FR 26035, May 4, 2000, as amended at 65 FR 76750, Dec.7, 2000; 66 FR 7065, Jan. 22, 2001; 66 FR 31104, June 8, 2001; 67 FR 1836, Jan. 14, 2002; 69 FR 38856, June 29, 2004; 71 FR 483, Jan. 4, 2006; 71 FR 768, Jan. 5, 2006; 71 FR 65652, Nov. 8, 2006]


### Appendix B to Subpart Q of Part 141—Standard Health Effects Language for Public Notification

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## Contaminant MCLG 1 

## mg/L MCL 2 

## mg/L Standard health effects language for public notification National Primary Drinking Water Regulations (NPDWR) A. Microbiological Contaminants 1a. Total coliform Zero See footnote 3 

## Coliforms are bacteria that are naturally present in the environment and are used as an indicator that other, potentially-harmful, bacteria may be present. Coliforms were found in more samples than allowed and this was a warning of potential problems. 1b. Fecal coliform/E. coli Zero Ze ro Fecal coliforms and E. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, and people with severely compromised immune systems. 1c. Fecal indicators (GWR): i. E. coli ii. enterococci iii. coliphage Zero None None TT TT TT Fecal indicators are microbes whose presence indicates that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term health effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, and people with severely compromised immune systems. 1d. Ground Water Rule (GWR) TT violations None TT Inadequately treated or inadequately protected water may contain disease-causing organisms. These organisms can cause symptoms such as diarrhea, nausea, cramps, 

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## and associated headaches. 2a. Turbidity (MCL) 4 

## None 1 NTU 5

## /5 NTU Turbidity has no health effects. However, turbidity can interfere with disinfection and provide a medium for microbial growth. Turbidity may indicate the presence of disease-causing organisms. These organisms include bacteria, viruses, and parasites that can cause symptoms such as nausea, cramps, diarrhea and associated headaches. 2b. Turbidity (SWTR TT) 6 

## None TT 7 

## Turbidity has no health effects. However, turbidity can interfere with disinfection and provide a medium for microbial growth. Turbidity may indicate the presence of disease-causing organisms. These organisms include bacteria, viruses, and parasites that can cause symptoms such as nausea, cramps, diarrhea and associated headaches. 2c. Turbidity (IESWTR TT and LT1ESWTR TT) 8 

## None TT Turbidity has no health effects. However, turbidity can interfere with disinfection and provide a medium for microbial growth. Turbidity may indicate the presence of disease-causing organisms. These organisms include bacteria, viruses, and parasites that can cause symptoms such as nausea, cramps, diarrhea and associated headaches. B. Surface Water Treatment Rule (SWTR), Interim Enhanced Surface Water Treatment Rule (IESWTR), Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR) and the Filter Backwas h Recycling Rule (FBRR) violations 3. Giardia lamblia (SWTR/IESWTR/LT1ESWTR) Zero TT 10 

## Inadequately treated watermay contain diseasecausing organisms. These organisms include bacteria, viruses, and parasites which can cause symptoms such as nausea, cramps, diarrhea, and associated headaches. 4. Viruses (SWTR/IESWTR/LT1ESWTR) 5. Heterotrophic plate count (HPC) bacteria 9 

## (SWTR/IESWTR/LT1ESWTR) 6. Legionella (SWTR/IESWTR/LT1ESWTR) 7. Cryptosporidium (IESWTR/FBRR/LT1ESWTR) C. Inorganic Chemicals (IOCs) 8. Antimony 0.006 0.006 Some people who drink water containing antimony well in excess of the MCL over many years could experience increases in 

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## blood cholesterol and decreases in blood sugar. 9. Arsenic 11 

## 0 0.010 Some people who drink water containing arsenic in excess of the MCL over many years could experience skin damage or problems with their circulatory system, and may have an increased risk of getting cancer. 10. Asbestos (10 μm) 7 MFL 12 

## 7 MFL Some people who drink water containing asbestos in excess of the MCL over many years may have an increased risk of developing benign intestinal polyps. 11. Barium 2 2 Some people who drink water containing barium in excess of the MCL over many years could experience an increase in their blood pressure. 12. Beryllium 0.004 0.004 Some people who drink water containing beryllium well in excess of the MCL over many years could develop intestinal lesions. 13. Cadmium 0.005 0.005 Some people who drink water containing cadmium in excess of the MCL over many years could experience kidney damage. 14. Chromium (total) 0.1 0.1 Some people who use water containing chromium well in excess of the MCL over many years could experience allergic dermatitis. 15. Cyanide 0.2 0.2 Some people who drink water containing cyanide well in excess of the MCL over many years could experience nerve damage or problems with their thyroid. 16. Fluoride 4.0 4.0 Some people who drink water containing fluoride in excess of the MCL over many years could get bone disease, including pain and tenderness of the bones. Fluoride in drinking water at half the MCL or more may cause mottling of children's teeth, usually in children less than nine years old. Mottling, also known as dental fluorosis, may include brown staining and/or pitting of the teeth, and occurs only in developing teeth before they erupt from the gums. 17. Mercury (inorganic) 0.002 0.002 Some people who drink water containing inorganic mercury well in excess of the MCL over many years could experience kidney damage. 18. Nitrate 10 10 Infants below the age of six months who drink water containing nitrate in excess 

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## of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue baby syndrome. 19. Nitrite 1 1 Infants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue baby syndrome. 20. Total Nitrate and Nitrite 10 10 Infants below the age of six months who drink water containing nitrate and nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue baby syndrome. 21. Selenium 0.05 0.05 Selenium is an essential nutrient. However, some people who drink water containing selenium in excess of the MCL over many years could experience hair or fingernail losses, numbness in fingers or toes, or problems with their circulation. 22. Thallium 0.0005 0.002 Some people who drink water containing thallium in excess of the MCL over many years could experience hair loss, changes in their blood, or problems with their kidneys, intestines, or liver. D. Lead and Copper Rule 23. Lead Zero TT 13 

## Infants and children who drink water containing lead in excess of the action level could experience delays in their physical or mental development. Children could show slight deficits in attention span and learning abilities. Adults who drink this water over many years could develop kidney problems or high blood pressure. 24. Copper 1.3 TT 14 

## Copper is an essential nutrient, but some people who drink water containing copper in excess of the action level over a relatively short amount of time could experience gastrointestinal distress. Some people who drink water containing copper in excess of the action level over many years could suffer liver or kidney damage. People with Wilson's Disease should consult their personal doctor. E. Synthetic Organic Chemicals (SOCs) 

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## 25. 2,4–D 0.07 0.07 Some people who drink water containing the weed killer 2,4–D well in excess of the MCL over many years could experience problems with their kidneys, liver, or adrenal glands. 26. 2,4,5–TP (Silvex) 0.05 0.05 Some people who drink water containing silvex in excess of the MCL over many years could experience liver problems. 27. Alachlor Zero 0.002 Some people who drink water containing alachlor in excess of the MCL over many years could have problems with their eyes, liver, kidneys, or spleen, or experience anemia, and may have an increased risk of getting cancer. 28. Atrazine 0.003 0.003 Some people who drink water containing atrazine well in excess of the MCL over many years could experience problems with their cardiovascular system or reproductive difficulties. 29. Benzo(a)pyrene (PAHs) Zero 0.0002 Some people who drink water containing benzo(a) pyrene in excess of the MCL over many years may experience reproductive difficulties and may have an increased risk of getting
cancer. 30. Carbofuran 0.04 0.04 Some people who drink water containing carbofuran in excess of the MCL over many years could experience problems with their blood, or nervous or reproductive systems. 31. Chlordane Zero 0.002 Some people who drink water containing chlordane in excess of the MCL over many years could experience problems with their liver or nervous system, and may have an increased risk of getting
cancer. 32. Dalapon 0.2 0.2 Some people who drink water containing dalapon well in excess of the MCL over many years could experience minor kidney changes. 33. Di(2-ethylhexyl) adipate 0.4 0.4 Some people who drink water containing di(2- ethylhexyl) adipate well in excess of the MCL over many years could experience toxic effects such as weight loss, liver enlargement or possible reproductive difficulties. 34. Di(2-ethylhexyl) phthalate Zero 0.006 Some people who drink water containing di(2- ethylhexyl) phthalate well in excess of the MCL over many years may have problems with their liver, or experience reproductive 

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## difficulties, and may have an increased risk of getting
cancer. 35. Dibromochloropropane (DBCP) Zero 0.0002 Some people who drink water containing DBCP in excess of the MCL over many years could experience reproductive difficulties and may have an increased risk of getting
cancer. 36. Dinoseb 0.007 0.007 Some people who drink water containing dinoseb well in excess of the MCL over many years could experience reproductive difficulties. 37. Dioxin (2,3,7,8-TCDD) Zero 3×10 − 8 

## Some people who drink water containing dioxin in excess of the MCL over many years could experience reproductive difficulties and may have an increased risk of getting
cancer. 38. Diquat 0.02 0.02 Some people who drink water containing diquat in excess of the MCL over many years could get cataracts. 39. Endothall 0.1 0.1 Some people who drink water containing endothall in excess of the MCL over many years could experience problems with their stomach or intestines. 40. Endrin 0.002 0.002 Some people who drink water containing endrin in excess of the MCL over many years could experience liver problems. 41. Ethylene dibromide Zero 0.00005 Some people who drink water containing ethylene dibromide in excess of the MCL over many years could experience problems with their liver, stomach, reproductive system, or kidneys, and may have an increased risk of getting
cancer. 42. Glyphosate 0.7 0.7 Some people who drink water containing glyphosate in excess of the MCL over many years could experience problems with their kidneys or reproductive difficulties. 43. Heptachlor Zero 0.0004 Some people who drink water containing heptachlor in excess of the MCL over many years could experience liver damage and may have an increased risk of getting
cancer. 44. Heptachlor epoxide Zero 0.0002 Some people who drink water containing heptachlor epoxide in excess of the MCL over many years could experience liver damage, and may have an increased risk of getting
cancer. 

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## 45. Hexachlorobenzene Zero 0.001 Some people who drink water containing hexachlorobenzene in excess of the MCL over many years could experience problems with their liver or kidneys, or adverse reproductive effects, and may have an increased risk of getting
cancer.46. Hexachlorocyclopentadiene 0.05 0.05 Some people who drink water containing hexachlorocyclopentadiene well in excess of the MCL over many years could experience problems with their kidneys or stomach. 47. Lindane 0.0002 0.0002 Some people who drink water containing lindane in excess of the MCL over many years could experience problems with their kidneys or liver. 48. Methoxychlor 0.04 0.04 Some people who drink water containing methoxychlor in excess of the MCL over many years could experience reproductive difficulties. 49. Oxamyl (Vydate) 0.2 0.2 Some people who drink water containing oxamyl in excess of the MCL over many years could experience slight nervous system effects. 50. Pentachlorophenol Zero 0.001 Some people who drink water containing pentachlorophenol in excess of the MCL over many years could experience problems with their liver or kidneys, and may have an increased risk of getting cancer. 51. Picloram 0.5 0.5 Some people who drink water containing picloram in excess of the MCL over many years could experience problems with their liver. 52. Polychlorinated biphenyls (PCBs) Zero 0.0005 Some people who drink water containing PCBs in excess of the MCL over many years could experience changes in their skin, problems with their thymus gland, immune deficiencies, or reproductive or nervous system difficulties, and may have an increased risk of getting cancer. 53. Simazine 0.004 0.004 Some people who drink water containing simazine in excess of the MCL over many years could experience problems with their blood. 54. Toxaphene Zero 0.003 Some people who drink water containing toxaphene in excess of the MCL over many years could have problems with their kidneys, liver, or 

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## thyroid, and may have an increased risk of getting
cancer. F. Volatile Organic Chemicals (VOCs) 55. Benzene Zero 0.005 Some people who drink water containing benzene in excess of the MCL over many years could experience anemia or a decrease in blood platelets, and may have an increased risk of getting
cancer. 56. Carbon tetrachloride Zero 0.005 Some people who drink water containing carbon tetrachloride in excess of the MCL over many years could experience problems with their liver and may have an increased risk of getting cancer. 57. Chlorobenzene (monochloro- benzene) 0.1 0.1 Some people who drink water containing chlorobenzene in excess of the MCL over many years could experience problems with their liver or kidneys. 58. o-Dichlorobenzene 0.6 0.6 Some people who drinkwater containing odichlorobenzene well in excess of the MCL over many years could experience problems with their liver, kidneys, or circulatory systems. 59. p-Dichlorobenzene 0.075 0.075 Some people who drinkwater containing pdichlorobenzene in excess of the MCL over many years could experience anemia, damage to their liver, kidneys, or spleen, or changes in their blood. 60. 1,2-Dichloroethane Zero 0.005 Some people who drink water containing 1,2- dichloroethane in excess of the MCL over many years may have an increased risk of getting cancer. 61. 1,1-Dichloroethylene 0.007 0.007 Some people who drink water containing 1,1- dichloroethylene in excess of the MCL over many years could experience problems with their liver. 62. cis-1,2-Dichloroethylene 0.07 0.07 Some people who drink water containing cis-1,2- dichloroethylene in excess of the MCL over many years could experience problems with their liver. 63. trans -1,2- Dichloroethylene 0.1 0.1 Some people who drink water containing trans-1,2- dichloroethylene well in excess of the MCL over many years could experience problems with their liver. 64. Dichloromethane Zero 0.005 Some people who drink water containing dichloromethane in excess of the MCL over many years could have liver problems and may have an 

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## increased risk of getting
cancer. 65. 1,2-Dichloropropane Zero 0.005 Some people who drink water containing 1,2- dichloropropane in excess of the MCL over many years may have an increased risk of getting
cancer. 66. Ethylbenzene 0.7 0.7 Some people who drink water containing ethylbenzene well in excess of the MCL over many years could experience problems with their liver or kidneys. 67. Styrene 0.1 0.1 Some people who drink water containing styrene well in excess of the MCL over many years could have problems with their liver, kidneys, or circulatory system. 68. Tetrachloroethylene Zero 0.005 Some people who drink water containing tetrachloroethylene in excess of the MCL over many years could have problems with their liver, and may have an increased risk of getting
cancer. 69. Toluene 1 1 Some people who drink water containing toluene well in excess of the MCL over many years could have problems with their nervous system, kidneys, or liver. 70. 1,2,4-Trichlorobenzene 0.07 0.07 Some people who drink water containing 1,2,4- trichlorobenzene well in excess of the MCL over many years could experience changes in their adrenal glands. 71. 1,1,1-Trichloroethane 0.2 0.2 Some people who drink water containing 1,1,1- trichloroethane in excess of the MCL over many years could experience problems with their liver, nervous system, or circulatory system. 72. 1,1,2-Trichloroethane 0.003 0.005 Some people who drink water containing 1,1,2- trichloroethane well in excess of the MCL over many years could have problems with their liver, kidneys, or immune systems. 73. Trichloroethylene Zero 0.005 Some people who drink water containing trichloroethylene in excess of the MCL over many years could experience problems with their liver and may have an increased risk of getting
cancer. 74. Vinyl chloride Zero 0.002 Some people who drink water containing vinyl chloride in excess of the MCL over many years may 

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## have an increased risk of getting cancer. 75. Xylenes (total) 10 10 Some people who drink water containing xylenes in excess of the MCL over many years could experience damage to their nervous system. G. Radioactive Contaminants 76. Beta/photon emitters Zero 4 mrem/yr 15 

## Certain minerals are radioactive and may emit forms of radiation known as photons and beta radiation. Some people who drink water containing beta and photon emitters in excess of the MCL over many years may have an increased risk of getting
cancer. 77. Alpha emitters Zero 17 pCi/L 17 

## Certain minerals are radioactive and may emit a form of radiation known as alpha radiation. Some people who drink water containing alpha emitters in excess of the MCL over many years may have an increased risk of getting
cancer. 78. Combined radium (226 & 228) Zero 5 pCi/L Some people who drink water containing radium 226 or 228 in excess of the MCL over many years may have an increased risk of getting cancer. 79. Uranium 16 

## Zero 30 μg/L Some people who drink water containing uranium in excess of the MCL over many years may have an increased risk of getting cancer and kidney toxicity. H. Disinfection Byproducts (DBPs), Byproduct Precursors, and Disinfectant

Residuals: Where disinfection is used in the treatment of drinking water, disinfectants combine with organic and inorganic matter present in water to form chemicals called disinfection byproducts (D BPs). EPA sets standards for controlling

the levels of disinfectants and DBPs in drinking water, including trihalomethanes (THMs) and haloacetic acids (HAAs) 18 

## 80. Total trihalomethanes (TTHMs) N/A 0.080 19,20 

## Some people who drink water containing trihalomethanes in excess of the MCL over many years may experience problems with their liver, kidneys, or central nervous system, and may have an increased risk of getting
cancer. 81. Haloacetic Acids (HAA) N/A 0.060 21 

## Some people who drink water containing haloacetic acids in excess of the MCL over many years may have an increased risk of getting
cancer. 82. Bromate Zero 0.010 Some people who drink water containing bromate in excess of the MCL over many years may have an increased risk of getting
cancer. 83. Chlorite 0.08 1.0 Some infants and young children who drink water containing chlorite in excess of the MCL could 

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## experience nervous system effects. Similar effects may occur in fetuses of pregnant women who drink water containing chlorite in excess of the MCL. Some people may experience anemia. 84. Chlorine 4 (MRDLG) 22 

## 4.0 (MRDL) 23 

## Some people who use water containing chlorine well in excess of the MRDL could experience irritating effects to their eyes and nose. Some people who drink water containing chlorine well in excess of the MRDL could experience stomach discomfort. 85. Chloramines 4 (MRDLG) 4.0 (MRDL) Some people who use water containing chloramines well in excess of the MRDL could experience irritating effects to their eyes and nose. Some people who drink water containing chloramines well in excess of the MRDL could experience stomach discomfort or anemia. 86a. Chlorine dioxide, where any 2 consecutive daily samples taken at the entrance to the distribution system are above the MRDL 0.8 (MRDLG) 0.8 (MRDL) Some infants and young children who drink water containing chlorine dioxide in excess of the MRDL could experience nervous system effects. Similar effects may occur in fetuses of pregnant women who drink water containing chlorine dioxide in excess of the MRDL. Some people may experience anemia. Add for public notification only:The chlorine dioxide violations reported today are the result of exceedances at the treatment facility only, not within the distribution system which delivers water to consumers. Continued compliance with chlorine dioxide levels within the distribution system minimizes the potential risk of these violations to consumers. 86b. Chlorine dioxide, where one or more distribution system samples are above the MRDL 0.8 (MRDLG) 0.8 (MRDL) Some infants and young children who drink water containing chlorine dioxide in excess of the MRDL could experience nervous system effects. Similar effects may occur in fetuses of pregnant women who drink water containing chlorine dioxide in excess of the MRDL. Some people may experience anemia. Add for public notification only:The chlorine dioxide violations reported today include exceedances of the EPA standard within the distribution system which 

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...A ppendix B—Endnotes
1. MCLG—Maximum contaminant level goal

2. MCL—Maximum contaminant level

3. For water systems analyzing at least 40 samples per month, no more than 5.0 percent of the monthly samples may be positive for total coliforms. For systems analyzing fewer than 40 samples per month, no more than one sample per month may be positive for total coliforms.

4. There are various regulations thatset turbidity standards for diffe rent types of systems, including 40 CFR 141.13, and the 1989 Surface Water Treatment Rule, the 1998 Interim Enhanced Surface Water Treatment Rule and the 2002 Long Term 1 Enhanced Surface Water Treatment Rule. The MCL for the monthly turbidity average is 1 NT U; the MCL for the 2-day avera ge is 5 NTU for systems that are required to filter but have not yet installed filtration (40 CFR 141.13).

5. NTU—Nephelometric turbidity unit

6. There are various regulations thatset turbidity standards for diffe rent types of systems, including 40 CFR 141.13, and the 1989 Surface Water Treatment Rule, the 1998 Interim Enhanced Surface Water Treatment Rule and the 2001 Long Term 1 Enhanced Surface Water Treatment Rule. Systems subject to the Surface Water Treatment Rule (both filtered and unfiltered) may not exceed 5 NTU. In addition, in filtered systems, 95 percent of samples each m onth must not exceed 0.5 NTU in systems using conventional or direct filtration and must not exce ed 1 NTU in systems using slow sand or diatomaceous earth filtration or other filtration techn ologies approved by the primacy agency.

7. TT—Treatment technique 

## delivers water to consumers. Violations of the chlorine dioxide standard within the distribution system may harm human health based on short-term exposures. Certain groups, including fetuses, infants, and young children, may be especially susceptible to nervous system effects from excessive chlorine dioxide exposure. 87. Control of DBP precursors (TOC) None TT Total organic carbon (TOC) has no health effects. However, total organic carbon provides a medium for the formation of disinfection byproducts. These byproducts include trihalomethanes (THMs) and haloacetic acids (HAAs). Drinking water containing these byproducts in excess of the MCL may lead to adverse health effects, liver or kidney problems, or nervous system effects, and may lead to an increased risk of getting
cancer. I. Other Treatment Techniques 88. Acrylamide Zero TT Some people who drink water containing high levels of acrylamide over a long period of time could have problems with their nervous system or blood, and may have an increased risk of getting
cancer. 89. Epichlorohydrin Zero TT Some people who drink water containing high levels of epichlorohydrin over a long period of time could experience stomach problems, and may have an increased risk of getting
cancer. 

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...8. There are various regulations thatset turbidity standards for diffe rent types of systems, including 40 CFR 141.13, the 1989 Surface Water Treatment Ru le (SWTR), the 1998 Interim Enhanced Surface Water Treatment Rule (IESWTR) and the 2002 Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR). For systems subject to the IESWTR (systems serving at le ast 10,000 people, using surface water or ground water under the direct i nfluence of surface water), that use conventional filtration or direct filtration, after January 1, 2002, the turbidity level of a system's combined filter effluent may not exceed 0.3 NTU in at least 95 percent of monthly measurements, and the turbidity level of a system's combined filter effluent mu st not exceed 1 NTU at any time. Systems subject to the IESWTR using technologies other than conventional, direct, sl ow sand, or diatomaceous earth filtration must meet turbidity limits set by the pr imacy agency. For systems subject to the LT1ESWTR (systems serving fewer than 10,000 people, using surface water or ground water under the direct influence of surface water) that use conventional filtration or direct fi ltration, after January 1, 2005, the turbidity level of a system's combined filter effluent may not exce ed 0.3 NTU in at least 95 percent of monthly measurements, and the turbidity level of a system's co mbined filter effluent must not exceed 1 NTU at any time. Systems subject to the LT 1ESWTR using technologies other than conventional, direct, slow sand, or diatomaceous earth filtration must meet turbidity limits set by the primacy agency.
9. The bacteria detected by heterotrophic plate count (H PC) are not necessarily harmful. HPC is simply an alternative method of determining disinfectant resi dual levels. The number of such bacteria is an indicator of whether there is enough disinfectant in the distribution system.

10. SWTR, IESWTR, and LT1ESWTR treatment technique violations that involve turbidity exceedances may use the health effects la nguage for turbidity instead.
11. These arsenic values are effective January 23, 2006. Until then, the MCL is 0.05 mg/L and there is no MCLG.

12. Millions fibers per liter.

13. Action Level = 0.015 mg/L
14. Action Level = 1.3 mg/L

15. Millirems per years
16. The uranium MCL is effective December 8, 2003 for all community water systems.

17. Picocuries per liter
18. Surface water systems and ground water systems under the dire ct influence of surface water are regulated under subpart H of 40 CFR 141. Subpart H community and non-transient non-community systems serving ≥ 10,000 must comply with subpart L DBP MC Ls and disinfectant maximum residual disinfectant levels (MRDLs) beginning January 1, 2002 . All other community and non-transient noncommunity systems must comply with subpart L DBP MCLs and disinfectant MRDLs beginning January 1, 2004. Subpart H transient non-community systems serving ≥ 10,000 that use chlorine dioxide as a disinfectant or oxidant must comply with the chlorine dioxide MRDL beginning January 1, 2002. All other transient non-community systems that use chlorine dioxide as a disinfectant or oxidant must comply with the chlorine dioxide MRDL beginning January 1, 2004.
19. Community and non-transient non-community system s must comply with subpart V TTHM and HAA5 MCLs of 0.080 mg/L and 0.060 mg/L, respectively (wit h compliance calculated as a locational running annual average) on the schedule in §141.620.

20. The MCL for total trihalomethanes is the sum of the concentrations of the indivi dual trihalomethanes.

21. The MCL for haloacetic acids is the sum of the concentrations of the individual haloacetic acids.

22. MRDLG—Maximum residual disinfectant level goal.

23. MRDL—Maximum residual disinfectant level.

[65 FR 26043, May 4, 2000; 65 FR 38629, June 21, 2000; 65 FR 40521, 40522, June 30, 2000, as amended at 65 FR 76751, Dec. 7, 2000; 66 FR 7065, Jan. 22, 2001; 66 FR 31104, June 8, 2001; 67 FR 1838, Jan. 14, 2002; 67 FR 70857, Nov. 27, 2002; 68 FR 14507, Mar. 25, 2003; 69 FR 38856, June 29, 2004; 71 FR 483, Jan. 4, 2006; 71 FR 65653, Nov. 8, 2006]


### Appendix C to Subpart Q of Part 141—List of Acronyms Used in Public Notification Regulation

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CCR Consumer Confidence Report
CWS Community Water System
DBP Disinfection Byproduct

EPA Environmental Protection Agency

GWR Ground Water Rule

HPC Heterotrophic Plate Count

IESWTR Interim Enhanced Surface Water Treatment Rule
IOC Inorganic Chemical

LCR Lead and Copper Rule

MCL Maximum Contaminant Level 

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...MCLG Maximum Contaminant Level Goal

MRDL Maximum Resi dual Disinfectant Level

MRDLG Maximum Residual Disinfectant Level Goal
NCWS Non-Community Water System

NPDWR National Primary Drinking Water Regulation
NTNCWS Non-Transient Non-Community Water System

NTU Nephelometric Turbidity Unit
OGWDW Office of Ground Water and Drinking Water

OW Office of Water

PN Public Notification

PWS Public Water System
SDWA Safe Drinking Water Act
SMCL Secondary Maximum Contaminant Level
SOC Synthetic Organic Chemical

SWTR Surface Water Treatment Rule

TCR Total Coliform Rule

TT Treatment Technique
TWS Transient Non-Community Water System
VOC Volatile Organic Chemical

[65 FR 26035, May 4, 2000, as amended at 71 FR 65653, Nov. 8, 2006]


### Subpart R [Reserved]

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### Subpart S—Ground Water Rule

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### Source: 71 FR 65653, Nov. 8, 2006, unless otherwise noted.
§ 141.400 General requirements and applicability.

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(a) Scope of this subpart. The requirements of this subpart S constitute National Primary Drinking Water Regulations.
(b) Applicability. This subpart applies to all public water systems that use ground water except that it does not apply to public water systems that combine all of their ground water with surface water or with ground water under the direct influence of surface water prior to treatment under subpart H. For the purposes of this subpart, “ground w ater system” is defined as any public water system meeting this applicability statement, including consecutive systems receiving finished ground water.
(c) General requirements. Systems subject to this subpart must comply with the following requirements:

(1) Sanitary survey information requi rements for all ground water systems as described in §141.401.
(2) Microbial source water monitoring requirements for ground water systems that do not treat all of their ground water to at least 99.99 percent (4-log) treatment of viruses (using inactivation, removal, or a State-approved combination of 4-log virus inactivation and removal) before or at the first customer as described in §141.402.
(3) Treatment technique requirements, described in §141.403, that apply to ground water systems that have fecally contaminated source waters, as dete rmined by source water monitoring conducted under §141.402, or that have significant deficiencies that are identified by the State or that are identified by EPA under SDWA section 1445. A ground water system with fecally contaminated source water or with significant deficiencies subject to the treatment tec hnique requirements of this subpart must implement one or more of the following corrective action opti ons: correct all significant deficiencies; provide an alternate source of water; eliminate the source of contamination; or provide treatment that reliably achieves at least 4-log treatment of viruses (using inactivation, removal, or a State-approved combination of 4-log virus inactivation and removal) before or at the first customer.
(4) Ground water systems that provide at least 4-log treatment of viruses (using inactivation, removal, or a State-approved combination of 4-log virus inactivati on and removal) before or at the first customer are required to conduct compliance monitoring to de monstrate treatment effectiveness, as described in §141.403(b). 

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...(5) If requested by the State, ground water systems mustprovide the State with any existing information that will enable the State to perform a hydrogeologic sensitivity assessment. Fo r the purposes of this subpart, “hydrogeologic sensitivity assessment” is a determination of whether ground water systems obtain water from hydrogeolog ically sensitive settings.
(d) Compliance date. Ground water systems must comply, unless otherwise noted, with the requirements of this subpart beginning December 1, 2009.


### § 141.401 Sanitary surveys for ground water systems.

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(a) Ground water systems must provide the State, at the State's request, any existing information that will enable the State to co nduct a sanitary survey.
(b) For the purposes of this subpart, a “sanitary surv ey,” as conducted by the State, includes but is not limited to, an onsite review of the water source(s) (i dentifying sources of contam ination by using results of source water assessments or other relevant infor mation where available), facilities, equipment, operation, maintenance, and monitoring compliance of a public water system to evaluate the adequacy of the system, its sources and operations and the distribution of safe drinking water.
(c) The sanitary survey must incl ude an evaluation of the applicable components listed in paragraphs (c) (1) through (8) of this section:
(1) Source,

(2) Treatment,
(3) Distribution system,
(4) Finished water storage,

(5) Pumps, pump facilities, and controls,
(6) Monitoring, reporting, and data verification,
(7) System management and operation, and
(8) Operator compliance with State requirements.


### § 141.402 Ground water source microbial monitoring and analytical methods.

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(a) Triggered source water monitoring —(1) General requirements. A ground water system must conduct triggered source water monitoring if the conditions ide ntified in paragraphs (a)(1)(i) and (a)(1)(ii) of this section exist.
(i) The system does not provide at le ast 4-log treatment of viruses (using inactivation, removal, or a State-approved combination of 4-log virus inactivation and removal) before or at the first customer for each ground water source; and
(ii) The system is notified that a sample collect ed under §141.21(a) is total coliform-positive and the sample is not invalidated under §141.21(c).
(2) Sampling requirements. A ground water system must collect, within 24 hours of notification of the total coliform-positive sample, at least one ground water source sample from each ground water source in use at the time the total coliform-positive sample was collected under §141.21(a), except as provided in paragraph (a)(2)(ii) of this section.
(i) The State may extend the 24-hour time limit on a case-by-case basis if the system cannot collect the ground water source water sample within 24 hours due to circumstances beyond its control. In the case of an extension, the State must specify how much time the system has to collect the sample.

(ii) If approved by the State, systems with more than one ground water source may meet the requirements of this paragraph (a)(2) by sampling a re presentative ground water source or sources. If directed by the State, systems must submit for S tate approval a triggered source water monitoring plan that identifies one or more ground water sources that are representative of each monitoring site in the system's sample siting plan under §141.21(a) and tha t the system intends to use for representative sampling under this paragraph.
(iii) A ground water system serving 1,000 people or fewer may use a repeat sample collected from a ground water source to meet both the requirements of §141.21(b) and to satisfy the monitoring requirements of paragraph (a)(2) of this section for that ground water source only if the State approves the use of E. coli as a fecal indicator for source water monitoring under this paragraph (a). If the repeat sample collected from the ground water source is E.coli positive, the system must comply with paragraph (a)(3) of this section.

(3) Additional requirements. If the State does not require corrective action under §141.403(a)(2) for a fecal indicator-positive source water sample collected under paragraph (a)(2) of this section that is not invalidated under paragraph (d) of this section, the system must collect five additional source water samples from the same source within 24 hours of being notified of the fecal indicator-positive sample.

(4) Consecutive and wholesale systems —(i) In addition to the other requirements of this paragraph (a), a consecutive ground water system that has a total co liform-positive sample collected under §141.21(a) must notify the wholesale system (s) within 24 hours of being notifi ed of the total coliform-positive sample.
(ii) In addition to the other requirements of this para graph (a), a wholesale ground water system must comply with paragraphs (a)(4)(ii)(A) and (a)(4)(ii)(B) of this section. 

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...(A) A wholesale ground water system that receives n otice from a consecutive system it serves that a sample collected under §141.21(a) is total coliform- positive must, within 24 hours of being notified, collect a sample from its ground water source(s) under paragraph (a)(2) of this section and analyze it for a fecal indicator under para graph (c) of this section.

(B) If the sample collected under paragraph (a)(4)(ii)(A ) of this section is fec al indicator-positive, the wholesale ground water system mustnotify all consecutive systems served by that ground water source of the fecal indicator source water positive within 24 hours of being notified of the ground water source sample monitoring result and must meet the requirements of paragraph (a)(3) of this section.

(5) Exceptions to the triggered source water monitoring requirements. A ground water system is not required to comply with the source water monitoring requirements of paragraph (a) of this section if either of the following conditions exists:
(i) The State determines, and documents in writin g, that the total coliform-positive sample collected under §141.21(a) is caused by a di stribution system deficiency; or
(ii) The total coliform-positive sample collected under §141.21(a) is collected at a location that meets State criteria for distri bution system conditions that will cause total coliform-positive samples.
(b) Assessment source water monitoring. If directed by the State, ground water systems must conduct assessment source water monitoring that meets S tate-determined requirements for such monitoring. A ground water system conducting assessment source w ater monitoring may use a triggered source water sample collected under paragraph (a)(2) of this section to meet the requirements of paragraph (b) of this section. State-determined assessment source water monitoring requirements may include:
(1) Collection of a total of 12 ground water source samples that represent each month the system provides ground water to the public,
(2) Collection of samples from each well unless the system obtains written St ate approval to conduct monitoring at one or more wells within the ground water system that are representative of multiple wells used by that system and that draw water from the same hydrogeologic setting,

(3) Collection of a standard sample volume of at least 10 0 mL for fecal indicator analysis regardless of the fecal indicator or analytical method used,
(4) Analysis of all ground water source samples us ing one of the analytical methods listed in the in paragraph (c)(2) of this section for the presence of E. coli , enterococci, or coliphage,
(5) Collection of ground water source samples at a location prior to any treatment of the ground water source unless the State approves a sampling location after treatment, and

(6) Collection of ground water source samples at the we ll itself unless the system's configuration does not allow for sampling at the well itself and the State approves an alternate sampling location that is representative of the water quality of that well.

(c) Analytical methods. (1) A ground water system subject to the source water monitoring requirements of paragraph (a) of this section must collect a standard sample volume of at least 100 mL for fecal indicator analysis regardless of the fecal indicator or analytical method used.
(2) A ground water system must analyze all ground water source samples collected under paragraph (a) of this section using one of the analytical methods listed in the following table in paragraph (c)(2) of this section or one of the alternative methods listed in appendix A to subpart C of this part for the presence of E. coli , enterococci, or coliphage:
Analytical Methods for Source Water Monitoring

A nalyses must be conducted in accordance with the documents listed below. The Director of the Federal Register approves the incorporation by reference of the documents listed in footnotes 2–11 in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the documents may be obtained from the sources listed below. Copies may be inspected at EPA's Drinking Water Docket, EPA West, 1301 

## Fecal indicator 1 

## Methodology Method citation E. coli Colilert 3 

## 9223 B. 2


## Colisure 3 

## 9223 B. 2 

## Membrane Filter Method with MI Agar EPA Method 1604. 4


## m-ColiBlue24 Test 5


## E*Colite Test 6


## EC–MUG 7 

## 9221 F. 2


## NA–MUG 7 

## 9222 G. 2 

## Enterococci Multiple-Tube Technique 9230B. 2 

## Membrane Filter Technique 9230C. 2 

## Membrane Filter Technique EPA Method 1600. 8


## Enterolert 9 

## Coliphage Two-Step Enrichment Presence-Absence Procedure EPA Method 1601. 10 

## Single Agar Layer Procedure EPA Method 1602. 11 

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...Constitution Avenue, NW., EPA West, Room B102, Washington DC 20460 (Telephone: 202–566–2426); or at the National Archives and Records Administrati on (NARA). For information on the availability of this material at NARA, call 202–741–6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

1 The time from sample collection to initiation of analysis may not exceed 30 hours. The ground water system is encouraged but is not required to hold samples below 10 °C during transit.

2 Methods are described in Standard Methods for the Examination of Water and Wastewater 20th edition (1998) and copies may be obtained from the American Public Health Association, 1015 Fifteenth Street, NW., Washington, DC 20005–2605.

3 Medium is available through IDEXX Laboratories, Inc., One IDEXX Drive, Westbrook, Maine 04092.

4 EPA Method 1604: Total Coliforms and Escherichia coli in Water by Membrane Filtration Using a Simultaneous Detection Technique (MI Medium); September 2002, EPA 821–R–02–024. Method is available at http://www.epa.gov/nerlcwww/1604sp02.pdf or from EPA's Water Resource Center (RC– 4100T), 1200 Pennsylvania Avenue, NW., Washington, DC 20460.

5A description of the m-ColiBlue24 Test, “Total Coliforms and E. coli Membrane Filtration Method with m-ColiBlue24 ® Broth,” Method No. 10029 Revision 2, August 17, 1999, is available from Hach Company, 100 Dayton Ave., Ames, IA 50010 or from EPA's Water Resource Center (RC–4100T), 1200 Pennsylvania Avenue, NW., Washington, DC 20460.

6 A description of the E*Colite Test, “Charm E*Colite Presence/Absence Test for Detection and Identification of Coliform Bacteria and Escherichia coli in Drinking Water, January 9, 1998, is available from Charm Sciences, Inc., 659 An dover St., Lawrence, MA 01843–1032 or from EPA's Water Resource Center (RC–4100T), 1200 Pennsylvania Avenue, NW., Washington, DC 20460.

7 EC–MUG (Method 9221F) or NA–MUG (Method 9222G) can be used for E. coli testing step as described in §141.21(f)(6)(i) or (ii) after use of Standard Methods 9221 B, 9221 D, 9222 B, or 9222 C.

8 EPA Method 1600: Enterococci in Water by Memb rane Filtration Using membrane-Enterococcus Indoxyl– β –D–Glucoside Agar (mEI) EPA 821–R–02–022 (September 2002) is an approved variation of Standard Method 9230C. The method is available at http://www.epa.gov/nerlcwww/1600sp02.pdf or from EPA's Water Resource Center (RC–4100T), 1200 Pennsylvania Avenue, NW., Washington, DC 20460. The holding time and temperature for ground water samples are specified in footnote 1 above, rather than as specified in Section 8 of EPA Method 1600.

9 Medium is available through IDEXX Laboratories, Inc., One IDEXX Drive, Westbrook, Maine 04092. Preparation and use of the medium is set forth in the article “Evaluation of Enterolert for Enumeration of Enterococci in Recreational Waters,” by Budnick, G.E., Howard, R.T., and Mayo, D.R., 1996, Applied and Environmental Microbiology, 62:3881–3884.

10 EPA Method 1601: Male-specific (F+) and Somatic Coliphage in Water by Two-step Enrichment Procedure; April 2001, EPA 821–R–01–030. Method is available at http://www.epa.gov/nerlcwww/1601ap01.pdf or from EPA's Water Resource Center (RC–4100T), 1200 Pennsylvania Avenue, NW., Washington, DC 20460.

11 EPA Method 1602: Male-specific (F+) and Somatic Coliphage in Water by Single Agar Layer (SAL) Procedure; April 2001, EPA 821–R–01–029. Method is available at http://www.epa.gov/nerlcwww/1602ap01.pdf or from EPA's Water Resource Center (RC–4100T), 1200 Pennsylvania Avenue, NW., Washington, DC 20460.
(d) Invalidation of a fecal indicator-posit ive ground water source sample . (1) A ground water system may obtain State invalidation of a fecal indicator-pos itive ground water source sample collected under paragraph (a) of this section only under the conditions specified in paragraphs (d)(1)(i) and (ii) of this section.
(i) The system provides the State wi th written notice from the laboratory that improper sample analysis occurred; or
(ii) The State determines and documents in writin g that there is substantial evidence that a fecal indicator-positive ground water source sample is not related to source water quality.
(2) If the State invalidates a fecal indicator-positive ground water source sample, the ground water system must collect another source water sample under paragraph (a) of this section within 24 hours of being notified by the State of its invalidation decisio n and have it analyzed for the same fecal indicator using the analytical methods in paragraph (c) of this section. The State may extend the 24-hour time limit on a case-by-case basis if the system cannot collect the source water sample within 24 hours due to circumstances beyond its control. In the case of an extension, the State must specify how much time the system has to collect the sample.
(e) Sampling location. (1) Any ground water source sample required under paragraph (a) of this section must be collected at a location prior to any trea tment of the ground water source unless the State approves a sampling location after treatment.
(2) If the system's configuration does not allow for sampling at the well itself, the system may collect a sample at a State-approved location to meet the r equirements of paragraph (a) of this section if the sample is representative of the water quality of that well.
(f) New sources. If directed by the State, a ground water sys tem that places a new ground water source into service after November 30, 2009, must conduct assessment source water monitoring under paragraph (b) of this section. If directed by the State, the system must begin monitoring before the ground water source is used to provide water to the public.
(g) Public notification. A ground water system with a ground water source sample collected under paragraph (a) or (b) of this section that is fecal indicator-positive and that is not invalidated under paragraph (d) of this section, incl uding consecutive systems served bythe ground water source, must conduct public notifi cation under §141.202.
(h) Monitoring violations. Failure to meet the requirements of paragraphs (a)–(f) of this section is a 

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...monitoring violation and requires the ground water s ystem to provide public notification under §141.204.

[71 FR 65653, Nov. 8, 2006; 71 FR 67427, Nov. 21, 2006, as amended at 74 FR 30958, June 29, 2009]


### § 141.403 Treatment technique requirements for ground water systems.

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(a) Ground water systems with significant deficiencies or source water fecal contamination. (1) The treatment technique requirements of this sect ion must be met by ground water systems when a significant deficiency is identified or when a ground water source sample collected under §141.402(a)(3) is fecal indicator-positive.
(2) If directed by the State, a ground water system wi th a ground water source sample collected under §141.402(a)(2), §141.402(a)(4), or §141.402(b) that is fecal indicator-positive must comply with the treatment technique requirements of this section.
(3) When a significant deficiency is identified at a Subpart H public water system that uses both ground water and surface water or ground water under the direct influence of surface water, the system must comply with provisions of this paragraph except in cases where the State determines that the significant deficiency is in a portion of the dist ribution system that is served solely by surface water or ground water under the direct influence of surface water.
(4) Unless the State directs the ground water system to implement a specific corrective action, the ground water system must consult with the State regarding the appropriate corrective action within 30 days of receiving written notice from the State of a signif icant deficiency, written notice from a laboratorythat a ground water source sample collected under §141.402(a)(3) was found to be fecal indicatorpositive, or direction from the State that a fecal indicator'positive collected under §141.402(a)(2), §141.402(a)(4), or §141.402(b) requires corrective acti on. For the purposes of th is subpart, significant deficiencies include, but are not limited to, defects in design, operation, or maintenance, or a failure or malfunction of the sources, treatmen t, storage, or distribution system that the State determines to be causing, or have potential for causing, the introd uction of contamination into the water delivered to
consumers.
(5) Within 120 days (or earlier if directed by the Sta te) of receiving written notification from the State of a significant deficiency, written notice from a laboratory that a ground water source sample collected under §141.402(a)(3) was found to be fecal indicator-positive, or direction from the State that a fecal indicatorpositive sample collected under §141.402(a)(2), §141.402(a)(4), or §141.402(b) requires corrective action, the ground water system must either:
(i) Have completed corrective action in accordance with applicable State plan review processes or other State guidance or direction, if any, includ ing State-specified interim measures; or
(ii) Be in compliance with a State-approved correcti ve action plan and schedule subject to the conditions specified in paragraphs (a)(5)(ii)(A) and (a)(5)(ii)(B) of this section.

(A) Any subsequent modifications to a State-approved corrective acti on plan and schedule must also be approved by the State.

(B) If the State specifies interim measures for prote ction of the public health pending State approval of the corrective action plan and schedu le or pending completion of the co rrective action plan, the system must comply with these interim measures as well as with any sc hedule specified by the State.
(6) Corrective action alternatives. Ground water systems that meet the cond itions of paragraph (a)(1) or (a)(2) of this section must implement one or more of the following corrective action alternatives:
(i) Correct all signi ficant deficiencies;

(ii) Provide an alternate source of water;
(iii) Eliminate the source of contamination; or
(iv) Provide treatment that reliably achieves at leas t 4-log treatment of viruses (using inactivation, removal, or a State-approved combination of 4-log vi rus inactivation and removal) before or at the first customer for the ground water source.
(7) Special notice to the public of significant deficiencies or source w ater fecal contamination. (i) In addition to the applicable publicnotification requirements of §141.202, a community ground water system that receives notice from the State of a sign ificant deficiency or notification of a fecal indicatorpositive ground water source sample that is not invalidated by the State under §141.402(d) must inform the public served by the water system under §141.153( h)(6) of the fecal indicator-positive source sample or of any significant deficiency that has not bee n corrected. The system must continue to inform the public annually until the significant deficiency is co rrected or the fecal contamin ation in the ground water source is determined by the State to be corrected under paragraph (a)(5) of this section.
(ii) In addition to the applicabl e public notification re quirements of §141.202, a non-community ground water system that receives notice from the State of a significant deficiency must inform the public served by the water system in a manner approved by the State of any significant deficiency that has not been corrected within 12 months of bein g notified by the State, or earlier if directed by the State. The system must continue to inform the public annually until the si gnificant deficiency is co rrected. The information must include:
(A) The nature of the significant deficiency and the date the significant deficiency was identified by the State;
(B) The State-approved plan and sched ule for correction of the significant deficiency, including interim measures, progress to date, and any interim measures completed; and
(C) For systems with a large proportion of non-Englis h speaking consumers, as determined by the State, information in the appropriate language(s) regarding the importance of the notice or a telephone number or address where consumers may contact the syste m to obtain a translated copy of the notice or assistance in the appropriate language. 

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...(iii) If directed by the State, a non- community water system with signif icant deficiencies that have been corrected must inform its customers of the signific ant deficiencies, how the deficiencies were corrected, and the dates of correction under paragraph (a)(7)(ii) of this section.

(b) Compliance monitoring —(1) Existing ground water sources. A ground water system that is not required to meet the source water monitoring requirements of this subpart for any ground water source because it provides at leas t 4-log treatment of viruses (using inactivation, removal, or a State-approved combination of 4-log virus inactivation and removal) before or at the first customer for any ground water source before December 1, 2009, must notify the State in writing that it provides at least 4-log treatment of viruses (using inactivation, removal, or a State- approved combination of 4-log virus inactivation and removal) before or at the first customer for the specified ground water source and begin compliance monitoring in accordance with paragraph (b)(3) of thi s section by December 1, 2009. Notification to the State must include engineering, operational, or other information that the State re quests to evaluate the submission. If the system subsequently discontinues 4-log treatment of viruses (using inactivation, removal, or a State-approved combination of 4-log vi rus inactivation and removal) before or at the first customer for a ground water source, the system mustconduct ground water source monitoring as required under §141.402.
(2) New ground water sources. A ground water system that places a ground water source in service after November 30, 2009, that is not required to meet the source water monitoring requirements of this subpart because the system provides at least 4-log treatment of viruses (using inactivation, removal, or a State-approved combination of 4-log virus inactivati on and removal) before or at the first customer for the ground water source must comply with the requirements of paragraphs (b)(2)(i), (b)(2)(ii) and (b)(2) (iii) of this section.
(i) The system must notify the State in writing that it provides at least 4-log treatment of viruses (using inactivation, removal, or a State-approved combinatio n of 4-log virus inactivation and removal) before or at the first customer for the ground water source. Noti fication to the State must include engineering, operational, or other information that the State requests to evaluate the submission.
(ii) The system must conduct compliance monito ring as required under §141.403(b)(3) of this subpart within 30 days of placing the source in service.
(iii) The system must conduct ground water so urce monitoring under §141.402 if the system subsequently discontinues 4-log treatment of viruses (using inactivation, removal, or a State-approved combination of 4-log virus inactivation and removal) before or at the first customer for the ground water
source.
(3) Monitoring requirements. A ground water system subject to the requirements of paragraphs (a), (b) (1) or (b)(2) of this section must monitor the effectiveness and reliability of treatment for that ground water source before or at the first customer as follows:

(i) Chemical disinfection —(A) Ground water systems serving greater than 3,300 people. A ground water system that serves greater than 3,300 people mu st continuously monitor the residual disinfectant concentration using analytical methods specified in §141.74(a)(2) at a location approved by the State and must record the lowest residual disinfecta nt concentration each day that water from the ground water source is served to the public. The ground water system must maintain the State-determined residual disinfectant concentration every day the ground water system serves water from the ground water source to the public. If there is a failure in the continuous monitoring equipment, the ground water system must conduct grab sampling every four hours until the continuous monitoring equipment is returned to service. The system must resume continu ous residual disinfectant monitoring within 14 days.
(B) Ground water systems serving 3,300 or fewer people. A ground water system that serves 3,300 or fewer people must monitor the residual disinfectantconcentration using analytical methods specified in §141.74(a)(2) at a location approved by the State and record the residual disinfection concentration each day that water from the ground water source is served to the public. The ground water system must maintain the State-determined residual disi nfectant concentration every day the ground water system serves water from the ground water source to the public. The ground water system must take a daily grab sample during the hour of peak flow or at another time specified by the State. If any daily grab sample measurement falls below the State-determined residual disinfectant concentration, the ground water system must take follow-up samples every four hours until the residual disinfectant concentration is restored to the State-determined level. Alternatively , a ground water system that serves 3,300 or fewer people may monitor continuously and meet the require ments of paragraph (b)(3)(i)(A) of this section.
(ii) Membrane filtration. A ground water system that uses membrane filtration to meet the requirements of this subpart must monitor the membrane filtration process in accordance with all State-specified monitoring requirements and must operate the membrane filtration in accordance with all State-specified compliance requirements. A ground water system that us es membrane filtration is in compliance with the requirement to achieve at least 4-log removal of viruses when:
(A) The membrane has an absolute molecular weig ht cut-off (MWCO), or an alternate parameter that describes the exclusion c haracteristics of the membrane, that can reli ably achieve at least 4-log removal of viruses;
(B) The membrane process is operated in accordance with State-specified compliance requirements; and
(C) The integrity of the membrane is intact.

(iii) Alternative treatment. A ground water system that uses a State-approved alternative treatment to meet the requirements of this subpart by providing at least 4-log treatment of viruses (using inactivation, removal, or a State-approved combination of 4-log vi rus inactivation and removal) before or at the first customer must:
(A) Monitor the alternative treatment in accordance with all State-specified monitoring requirements; and
(B) Operate the alternative treatment in accordance with all compliance requirements that the State determines to be necessary to achieve at least 4-log treatment of viruses.
(c) Discontinuing treatment. A ground water system may discontinue 4-log treatment of viruses (using inactivation, removal, or a State-approved combinatio n of 4-log virus inactivation and removal) before or at the first customer for a ground water source if the State determines and documents in writing that 4- log treatment of viruses is no longer necessary for that ground water source. A system that discontinues 4-log treatment of viruses is subject to the source water monitoring and analytical methods requirements of §141.402 of this subpart. 

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...(d) Failure to meet the monitoring requirements of paragraph (b) of this section is a monitoring violation and requires the ground water system to provide public notification under §141.204.


### § 141.404 Treatment technique violations for ground water systems.

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(a) A ground water system with a significant defici ency is in violation of the treatment technique requirement if, within 120 days (or ea rlier if directed by the State) of receiving written notice from the State of the significant deficiency, the system:
(1) Does not complete corrective action in accordance with any applicable State plan review processes or other State guidance and direction, including State specified interim ac tions and measures, or
(2) Is not in compliance with a State-approved corrective action plan and schedule.
(b) Unless the State invalidates a fecal indicator-positive ground water source sample under §141.402 (d), a ground water system is in violation of the treatment technique requirement if, within 120 days (or earlier if directed by the State) of meeting the conditions of §141.403(a)(1) or §141.403(a)(2), the system:
(1) Does not complete corrective action in accordance with any applicable State plan review processes or other State guidance and direction, incl uding State-specified interim measures, or

(2) Is not in compliance with a State-approved corrective action plan and schedule.
(c) A ground water system subject to the requirements of §141.403(b)(3) that fails to maintain at least 4- log treatment of viruses (using inactivation, removal, or a State-approved combination of 4-log virus inactivation and removal) before or at the first customer for a ground wa ter source is in violation of the treatment technique requirement if the failure is not corrected within four hours of determining the system is not maintaining at least 4-log treatm ent of viruses before or at the first customer.
(d) Ground water system must give public noti fication under §141.203 for the treatment technique violations specified in paragraphs (a), (b) and (c) of this section.


### § 141.405 Reporting and recordkeeping for ground water systems.

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(a) Reporting. In addition to the requirements of §141.31, a ground water system regulated under this subpart must provide the fol lowing information to the State:

(1) A ground water system conducting compliance monitoring under §141.403(b) must notify the State any time the system fails to meet any State-specifi ed requirements including, but not limited to, minimum residual disinfectant concentration, membrane operati ng criteria or membrane integrity, and alternative treatment operating criteria, if operation in accordanc e with the criteria or requirements is not restored within four hours. The ground water system must notify the State as soon as possible, but in no case later than the end of the next business day.
(2) After completing any corrective action under §141.403(a), a ground water system must notify the State within 30 days of completi on of the corrective action.

(3) If a ground water system subject to the requirements of §141.402(a) does not conduct source water monitoring under §141.402(a)(5)(ii), the system must provide documentation to the State within 30 days of the total coliform positive sample that it met the State criteria.
(b) Recordkeeping. In addition to the requirements of §141.33, a ground water system regulated under this subpart must maintain the following information in its records:
(1) Documentation of corrective actions. Documentati on shall be kept for a period of not less than ten years.
(2) Documentation of notice to the public as required under §141.403(a)(7). Documentation shall be kept for a period of not less than three years.

(3) Records of decisions under §141.402(a)(5)(ii) and records of invalidation of fecal indicator-positive ground water source samples under §141.402(d). Documentation shall be kept for a period of not less than five years.

(4) For consecutive systems , documentation of notific ation to the wholesale sy stem(s) of total-coliform positive samples that are not invalidated under §141.21(c). Documentation shall be kept for a period of not less than five years.
(5) For systems, including wholesale systems, that are required to perform compliance monitoring under §141.403(b):
(i) Records of the State-specified minimum disinfectant residual. Documentation shall be kept for a period of not less than ten years.
(ii) Records of the lowest daily residual disinfecta nt concentration and records of the date and duration of any failure to maintain the State-prescribed minimu m residual disinfectant concentration for a period of more than four hours. Documentation shall be kept for a period of not less than five years.

(iii) Records of State-specified compliance requir ements for membrane filtration and of parameters specified by the State for State-approved alternativ e treatment and records of the date and duration of any failure to meet the membrane operating, membrane integrity, or alternative treatment operating requirements for more than four hours. Documentation shal l be kept for a period of not less than five years.


### Subpart T—Enhanced Filtration and Disinfection—Systems Serving Fewer Than 10,000 

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...

### People

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### Source: 67 FR 1839, Jan. 14, 2002, unless otherwise noted.
General Requirements

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### § 141.500 General requirements.

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The requirements of this subpart constitute natio nal primary drinking water regulations. These regulations establish requirements for filtration and di sinfection that are in addition to criteria under which filtration and disinfection are required under subpart H of this part. The regulations in this subpart establish or extend treatment technique requirements in lieu of maximum contaminant levels for the following contaminants: Giardia lamblia, viruses, heterotrophic plate count bacteria, Legionella, Cryptosporidium and turbidity. The treatment technique requirements consist of installing and properly operating water treatment processes which reliably achieve:
(a) At least 99 percent (2 log) removal of Cryptosporidium between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer for filtered systems, or Cryptosporidium control under the watershed control plan for unfiltered systems; and
(b) Compliance with the profiling and benchmark requirements in §§141.530 through 141.544.


### § 141.501 Who is subject to the requirements of subpart T?

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You are subject to these requi rements if your system:
(a) Is a public water system;

(b) Uses surface water or GWUDI as a source; and
(c) Serves fewer than 10,000 persons.


### § 141.502 When must my system comply with these requirements?

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You must comply with these requirements in this subpart beginning January 1, 2005, except where otherwise noted.

[69 FR 38856, June 29, 2004]


### § 141.503 What does subpart T require?

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There are seven requirements of this subpart, and you must comply with all requirements that are applicable to your system . These requirements are:
(a) You must cover any finished water reservoir that you began to c onstruct on or after March 15, 2002 as described in §§141.510 and 141.511;
(b) If your system is an unfiltered system, y ou must comply with the updated watershed control requirements described in §§141.520–141.522;
(c) If your system is a community or non-transi ent non-community water sys tems you must develop a disinfection profile as described in §§141.530–141.536;

(d) If your system is considering making a signific ant change to its disinfection practices, you must develop a disinfection benchmark and consult with the State for approval of the change as described in §§141.540–141.544;
(e) If your system is a filtered system, you must comp ly with the combined fil ter effluent requirements as described in §§141.550–141.553;
(f) If your system is a filtered system that uses conventi onal or direct filtration, you must comply with the individual filter turbidity require ments as described in §§141.560–141.564; and
(g) You must comply with the applicable reportin g and recordkeeping requirements as described in §§141.570 and 141.571.



### Finished Water Reservoirs

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### § 141.510 Is my system subject to the new finished water reservoir requirements? 

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A ll subpart H systems which serve fewer than 10,000 are subject to this requirement.


### § 141.511 What is required of new finished water reservoirs?

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If your system begins c onstruction of a finished water reservoir on or after Ma rch 15, 2002 the reservoir must be covered. Finished water reservoirs for which your system began construction prior to March 15, 2002 are not subject to this requirement.


### Additional Watershed Control Requirements for Unfiltered Systems

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### § 141.520 Is my system subject to the updated watershed control requirements?

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If you are a subpart H system serving fewer than 10,000 persons which does not provide filtration, you must continue to comply with all of the filtration avoi dance criteria in §141.71, as well as the additional watershed control requirements in §141.521.


### § 141.521 What updated watershed control requirements must my unfiltered system implement to continue to avoid filtration?

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Your system must take any additi onal steps necessary to minimize the potential for contamination by Cryptosporidium oocysts in the source water. Your system's watershed control program must, for Cryptosporidium :
(a) Identify watershed characteristics and activities which may have an adverse effect on source water quality; and
(b) Monitor the occurrence of activi ties which may have an adverse effect on source water quality.


### § 141.522 How does the State determine whether my system's watershed control requirements are adequate?

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During an onsite inspection conducted under the provisions of §141.71(b)(3), the State must determine whether your watershed control program is adequate to limit potential contamination by Cryptosporidium oocysts. The adequacy of the program must be based on the comprehensiveness of the watershed review; the effectiveness of your program to monitor and control detrimental acti vities occurring in the watershed; and the extent to which your system has ma ximized land ownership and/or controlled land use within the watershed.



### Disinfection Profile

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### § 141.530 What is a disinfection profile and who must develop one?

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Adisinfection profile is a graphical re presentation of your system's level of Giardia lamblia or virus inactivation measured during the co urse of a year. If you are a subpart H community or non-transient non-community water system which serves fewer than 10,000 persons, your system must develop a disinfection profile unless your S tate determines that your system's prof ile is unnecessary. Your State may approve the use of a more representative data set for disinfection profiling than the data set required under §§141.532–141.536.

[67 FR 1839, Jan. 14, 2002, as amended at 69 FR 38856, June 29, 2004]


### § 141.531 What criteria must a State use to determine that a profile is unnecessary?

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States may only determine that a system's profile is unnecessary if a system's TTHM and HAA5 levels are below 0.064 mg/L and 0.048 mg/L, respectively. To determine these levels, TTHM and HAA5 samples must be collected after January 1, 1998, during the month with the warmest water temperature, and at the point of maximum residence time in your distribution system. Your State may approve a more representative TTHM and HAA5 data set to determine these levels.

[67 FR 1839, Jan. 14, 2002, as amended at 69 FR 38856, June 29, 2004]


### § 141.532 How does my system develop a disinfection profile and when must it begin?

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...Adisinfection profile consists of three steps:
(a) First, your system must collect data for several parameters from the plant as discussed in §141.533 over the course of 12 months. If your system serv es between 500 and 9,999 persons you must begin to collect data no later than July 1, 2003. If your system serves fewer than 500 persons you must begin to collect data no later than January 1, 2004.
(b) Second, your system must use this data to calc ulate weekly log inacti vation as discussed in §§141.534 and 141.535; and
(c) Third, your system must use these weekly log inactivations to develop a disinfection profile as specified in §141.536.


### § 141.533 What data must my system collect to calculate a disinfection profile?

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Your system must monitor the following parameters to determine the total log inactivation using the analytical methods in §141.74 (a), once per week on the same calendar day, over 12 consecutive months:
(a) The temperature of the disinfected water at each residual disinfectant concentration sampling point during peak hourly flow;

(b) If your system uses chlorine, the pH of the di sinfected water at each residual disinfectant concentration sampling point during peak hourly flow;
(c) The disinfectant contact time(s) (“T”) during peak hourly flow; and
(d) The residual disinfectant concentration(s) (“C”) of the water before or at the first customer and prior to each additional point of disinfection during peak hourly flow.


### § 141.534 How does my system use this data to calculate an inactivation ratio?

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Use the tables in §141.74(b)(3)(v) to determine the appropriate CT99.9 value. Calculate the total inactivation ratio as follows, and multiply the value by 3.0 to determine log inactivation of Giardia lamblia:

[67 FR 1839, Jan. 14, 2002, as amended at 69 FR 38856, June 29, 2004]


### § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

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If your system uses chloramines, ozone, or chlori ne dioxide for primary disinfection, you must also calculate the logs of inac tivation for viruses and develop an add itional disinfection profile for viruses using methods approved by the State.


### § 141.536 My system has developed an inactivation ratio; what must we do now?

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Each log inactivation serves as a data point in yo ur disinfection profile. Your system will have obtained 52 measurements (one for every week of the year). This will allow your system and the State the opportunity to evaluate how microbial inactivation varied over the course of the year by looking at all 52 measurements (your Disinfection Profile). Your sy stem must retain the Disinfection Profile data in graphic form, such as a spreadsheet, which must be available for review bythe State as part of a sanitary survey. Your system mu st use this data to calculate a benchmark if you are considering changes to disinfection practices.



## If your system * * * Your system must determine * * * (a) Uses only one point of disinfectant application (1) One inactivation ratio (CTcalc/CT 99.9 

## ) before or at the first customer during peak hourly flow
or (2) Successive CTcalc/CT 99.9 

## values, representing sequential inactivation ratios, between the point of disinfectant application and a point before or at the first customer during peak hourly flow. Under this alternative, your system must calculate the total inactivation ratio by determining (CTcalc/CT 99.9 

## ) for each sequence and then adding the (CTcalc/CT 99.9 

## ) values together to determine ( Σ CTcalc/CT 99.9 

## ). (b) Uses more than one point of disinfectant application before the first customer The (CTcalc/CT 99.9 

## ) value of each disinfection segment immediately prior to the next point of disinfectant application, or for the final segment, before or at the first customer, during peak hourly flow using the procedure specified in paragraph (a)(2) of this section. 

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...

### Disinfection Benchmark

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### § 141.540 Who has to develop a disinfection benchmark?

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If you are a subpart H system required to develop a disinfection profile under §§141.530 through 141.536, your system must develop a Disinfection Benchmark if you decide to make a significant change to your disinfection practi ce. Your system must consult with the State for approval before you can implement a significant di sinfection practice change.


### § 141.541 What are significant changes to disinfection practice?

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Significant changes to disinfec tion practice include:
(a) Changes to the point of disinfection;
(b) Changes to the disinfectant(s) used in the treatment plant;
(c) Changes to the disinfection process; or

(d) Any other modification identified by the State.


### § 141.542 What must my system do if we are considering a significant change to disinfection practices?

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If your system is considering a si gnificant change to its disinfection practice, your system must calculate a disinfection benchmark(s) as described in §§14 1.543 and 141.544 and provide the benchmark(s) to your State. Your system may only make a significan t disinfection practice c hange after consulting with the State for approval. Your system must submit t he following information to the State as part of the consultation and approval process:
(a) A description of the proposed change;
(b) The disinfection profile for Giardia lamblia (and, if necessary, viruses) and disinfection benchmark;

(c) An analysis of how the proposed change wi ll affect the current levels of disinfection; and
(d) Any additional information requested by the State.


### § 141.543 How is the disinfection benchmark calculated?

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If your system is making a significant change to its disi nfection practice, it must calculate a disinfection benchmark using the procedure specified in the following table.



### § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

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If your system uses chloramines, oz one or chlorine dioxide for primary disinfection your system must calculate the disinfection benchmark from the data your system collected for viruses to develop the disinfection profile in addition to the Giardia lamblia disinfection benchmark calculated under §141.543. This viral benchmark must be calculated in the same manner used to calculate the Giardia lamblia disinfection benchmark in §141.543.


### Combined Filter Effluent Requirements

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### § 141.550 Is my system required to meet subpart T combined filter effluent turbidity limits?



## To calculate a disinfection benchmark your system must perform the following steps Step 1: Using the data your system collected to develop the Disinfection Profile, determine the average Giardia lamblia inactivation for each calendar month by dividing the sum of all Giardia lamblia inactivations for that month by the number of values calculated for that month. Step 2: Determine the lowest monthly average value out of the twelve values. This value becomes the disinfection benchmark. 

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A ll subpart H systems which serv e populations fewer than 10,000, are required to filter, and utilize filtration other than slow sand filtration or diatomac eous earth filtration must meet the combined filter effluent turbidity requirements of §§141.551–141.553 . If yo ur system uses slow sand or diatomaceous earth filtration you are not required to meet the combined filter effluent turbidity limits of subpart T, but you must continue to meet the combined filter effluent turbidity limits in §141.73.


### § 141.551 What strengthened combined filter effluent turbidity limits must my system meet?

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Your system must meet two strengthened combined filter effluent turbidity limits.
(a) The first combined filter effluent turbidity limit is a “95th percentile” turbidity limit that your system must meet in at least 95 percent of the turbidity measurements taken each month. Measurements must continue to be taken as described in §141.74(a) and (c). Monthly reporting must be completed according to §141.570. The following table describes the required limits for spec ific filtration technologies.

(b) The second combined filter effluent turbidity limit is a “maximum” turbidity limit which your system may at no time exceed during the month. Measurements must continue to be taken as described in §141.74(a) and (c). Monthly reporting must be completed according to §141.570. The following table describes the required limits for specific filtration technologies.

[67 FR 1839, Jan. 14, 2002, as amended at 69 FR 38856, June 29, 2004]


### § 141.552 My system consists of “alternative filtration” and is required to conduct a demonstration—what is required of my system and how does the State establish my turbidity limits?

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(a) If your system consists of alternative filtration (filtration other than slow sand filtration, diatomaceous earth filtration, conventional filtrati on, or direct filtration) you are required to conduct a demonstration (see tables in §141.551). Your system must dem onstrate to the State, using pilot plant studies or other means, that your system's filtration, in combination with disinfection treatment, consistently achieves:
(1) 99 percent removal of Cryptosporidium oocysts;
(2) 99.9 percent removal and/or inactivation of Giardia lamblia cysts; and
(3) 99.99 percent removal and/or inactivation of viruses.

(b) [Reserved]


### § 141.553 My system practices lime softening—is there any special provision regarding my combined filter effluent?

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If your system practices lime softening, you may acidif y representative combined filter effluent turbidity samples prior to analysis using a protocol approved by the State.


### Individual Filter Turbidity Requirements

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### § 141.560 Is my system subject to individual filter turbidity requirements?

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## If your system consists of * * * Your 95th percentile turbidity value is * * * (1) Conventional Filtration or Direct Filtration 0.3 NTU.

(2) All other “Alternative” Filtration A value determined by the State (not to exceed 1 NTU) based on the demonstration described in §141.552.

If your system consists of * * * Your maximum turbidity value is * * * (1) Conventional Filtration or Direct Filtration 1 NTU.

(2) All other “Alternative Filtration” A value determined by the State (not to exceed 5 NTU) based on the demonstration as described in §141.552. 

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...If your system is a subpart H system servin g fewer than 10,000 people and utilizing conventional filtration or direct filtration, you must conduct continu ous monitoring of turbidity for each individual filter at your system. The following requirements apply to continuous turbidity monitoring:
(a) Monitoring must be conducted usin g an approved method in §141.74(a);
(b) Calibration of turbidimeters must be conducte d using procedures specif ied by the manufacturer;
(c) Results of turbidity monitoring mustbe recorded at least every 15 minutes;
(d) Monthly reporting must be completed according to §141.570; and
(e) Records must be maintained according to §141.571.


### § 141.561 What happens if my system's turbidity monitoring equipment fails?

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If there is a failure in the continuous turbidity moni toring equipment, your system must conduct grab sampling every four hours in lieu of continuous mo nitoring until the turbidimeter is back on-line. Your system has 14 days to resume continuous mo nitoring before a violation is incurred.


### § 141.562 My system only has two or fewer filters—is there any special provision regarding individual filter turbidity monitoring?

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Yes, if your system only consists of two or fe wer filters, you may conduct continuous monitoring of combined filter effluent turbidity in lieu of individual filter efflu ent turbidity monitoring. Continuous monitoring must meet the same requirements set forth in §141.560(a) through (d) and §141.561.


### § 141.563 What follow-up action is my system required to take based on continuous turbidity monitoring?

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Follow-up action is required acco rding to the following tables:


## If * * * Your system must * * * (a) The turbidity of an individual filter (or the turbidity of combined filter effluent (CFE) for systems with 2 filters that monitor CFE in lieu of individual filters) exceeds 1.0 NTU in two consecutive recordings 15 minutes apart Report to the State by the 10th of the following month and include the filter number(s), corresponding date(s), turbidity value(s) which exceeded 1.0 NTU, and the cause (if known) for the exceedance(s).

If a system was required to report to

the State * * * Your system must * * * (b) For three months in a row and turbidity exceeded 1.0 NTU in two consecutive recordings 15 minutes apart at the same filter (or CFE for systems with 2 filters that monitor CFE in lieu of individual filters) Conduct a self-assessment of the filter(s) within 14 days of the day the filter exceeded 1.0 NTU in two consecutive measurements for the third straight month unless a CPE as specified in paragraph (c) of this section was required. Systems with 2 filters that monitor CFE in lieu of individual filters must conduct a self assessment on both filters. The self-assessment must consist of at least the following components: assessment of filter performance; development of a filter profile; identification and prioritization of factors limiting filter performance; assessment of the applicability of corrections; and preparation of a filter self-assessment report. (c) For two months in a row and turbidity exceeded 2.0 NTU in 2 consecutive recordings 15 minutes apart at the same filter (or CFE for systems with 2 filters that monitor CFE in lieu of individual filters) Arrange to have a comprehensive performance evaluation (CPE) conducted by the State or a third party approved by the State not later than 60 days following the day the filter exceeded 2.0 NTU in two consecutive measurements for the second straight month. If a CPE has been completed by the State or a third party approved by the State within the 12 prior months or the system and State are jointly participating in an ongoing Comprehensive Technical Assistance (CTA) project at the system, a new CPE is not required. If conducted, a CPE must be completed and submitted to the State no later than 120 days following the day the filter exceeded 2.0 NTU in two consecutive measurements for the second straight month. 

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...[67 FR 1839, Jan. 14, 2002, as amended at 69 FR 38856, June 29, 2004]


### § 141.564 My system practices lime softening—is there any special provision regarding my individual filter turbidity monitoring?

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If your system utilizes lime softening, you may appl y to the State for alternative turbidity exceedance levels for the levels specified in the table in §141 .563. You must be able to demonstrate to the State that higher turbidity levels are due to lime carryover only, and not due to degraded filter performance.


### Reporting and Recordkeeping Requirements

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### § 141.570 What does subpart T require that my system report to the State?

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This subpart T requires your system to report severa l items to the State. The following table describes the items which must be reported and the frequency of reporting. Your system is required to report the information described in the following table, if it is subject to the specific requirement shown in the first column.



## Corresponding

requirement Description of information to report Frequency (a) Combined Filter Effluent Requirements (§§141.550– 141.553) (1) The total number of filtered water turbidity measurements taken during the month By the 10th of the following month.

(2) The number and percentage of filtered water turbidity measurements taken during the month which are less than or equal to your system's required 95th percentile limit By the 10th of the following month.

(3) The date and value of any turbidity measurements taken during the month which exceed the maximum turbidity value for your filtration system By the 10th of the following month.

(b) Individual Turbidity Requirements (§§141.560– 141.564) (1) That your system conducted individual filter turbidity monitoring during the month By the 10th of the following month.

(2) The filter number(s), corresponding date(s), and the turbidity value(s) which exceeded 1.0 NTU during the month, and the cause (if known) for the exceedance(s), but only if 2 consecutive measurements exceeded 1.0 NTU By the 10th of the following month.

(3) If a self-assessment is required, the date that it was triggered and the date that it was completed By the 10th of the following month (or 14days after the selfassessment wastriggered only if the selfassessment was triggered during the last four days of the month) (4) If a CPE is required, that the CPE is required and the date that it was triggered By the 10th of the following month.
(5) Copy of completed CPE report Within 120 days after the CPE was triggered. (c) Disinfection Profiling (§§141.530– 141.536) (1) Results of optional monitoring which show TTHM levels <0.064 mg/l and HAA5 levels <0.048 mg/l (Only if your system wishes to forgo profiling) or that your system has begun disinfection profiling (i) For systems serving 500–9,999 by July 1, 2003; (ii) For systems serving fewer than 500 by January 1, 2004.
(d) Disinfection (1) A description of the proposed Anytime your system is 

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...[67 FR 1839, Jan. 14, 2002, as amended at 69 FR 38857, June 29, 2004]


### § 141.571 What records does subpart T require my system to keep?

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Your system must keep several types of records bas ed on the requirements of subpart T, in addition to recordkeeping requirements under §141.75. The followi ng table describes the necessary records, the length of time these records must be kept, and for whic h requirement the records pertain. Your system is required to maintain records described in this table, if it is subject to the s pecific requirement shown in the first column.



### Subpart U—Initial Distribution System Evaluations

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### Source: 71 FR 483, Jan. 4, 2006, unless otherwise noted.
§ 141.600 General requirements.

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(a) The requirements of subpart U of this part constitut e national primary drinking water regulations. The regulations in this subpart establish monitorin g and other requirements for identifying subpart V compliance monitoring locations for determining comp liance with maximum contaminant levels for total trihalomethanes (TTHM) and haloacetic acids (five)(HAA5). You must us e an Initial Di stribution System Evaluation (IDSE) to determine locations with representative high TTHM and HAA5 concentrations throughout your distribution system. IDSEs are us ed in conjunction with, but separate from, subpart L compliance monitoring, to identify and selectsubpart V compliance monitoring locations.
(b) Applicability. You are subject to thes e requirements if your system is a community water system that uses a primary or residual disinfectant other than ultrav iolet light or delivers water that has been treated with a primary or residual disinfectant other than ul traviolet light; or if your system is a nontransient noncommunity water system that se rves at least 10,000 people and uses a primary or residual disinfectant other than ultraviolet light or delivers water that has been treated with a primary or residual disinfectant other than ultraviolet light.
(c) Schedule. (1) You must comply with the requirements of this subpart on the schedule in the table in this paragraph (c)(1). 

## Benchmarking (§§141.540– 141.544) change in disinfection, your system's disinfection profile for Giardia lamblia (and, if necessary, viruses) and disinfection benchmark, and an analysis of how the proposed change will affect the current levels of disinfection considering a significant change to its disinfection practice.

Corresponding

requirement Description of necessary records Duration of time records must be kept (a) Individual Filter Turbidity Requirements (§§141.560–141.564) Results of individual filter monitoring At least 3 years.

(b) Disinfection Profiling (§§141.530–141.536) Results of Profile (including raw data and analysis) Indefinitely.

(c) Disinfection Benchmarking (§§141.540–141.544) Benchmark (including raw data and analysis) Indefinitely.

If you serve this population You must submit your standard monitoring plan or system specific

study plan 1 

## or 40/30 certification 2 

## to the State by or receive very small

system waiver from State You must complete your standard monitoring or system specific study by You must submit your IDSE report to the State by 3 

## Systems that are not part of a combined distribution system and systems that serve the largest population in the combined distribution system (i) ≥ 100,000 October 1, 2006 September 30, 2008 January 1, 2009.
(ii) 50,000– 99,999 April 1, 2007 March 31, 2009 July 1, 2009.
(iii) 10,000– October 1, 2007 September 30, January 1, 2010. 

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...1 If, within 12 months after the date identified in this column, the State does not approve your plan or notify you that it has not yet completed its review , you may consider the plan that you submitted as approved. You must implement that plan and you mu st complete standard monitoring or a system specific study no later than the date identified in the third column.

2 You must submit your 40/30 certification under §141.603 by the date indicated.

3 If, within three months after the date identified in this column (nine months after the date identified in this column if you must comply on the schedule in paragraph (c)(1)(iii) of this section), the State does not approve your IDSE report or notify you that it has no t yet completed its review, you may consider the report that you submitted as approved and you mustimplement the recommended subpart V monitoring as required.
(2) For the purpose of the schedule in paragraph (c)(1) of this section, the State may determine that the combined distribution system does not include cert ain consecutive systems based on factors such as receiving water from a wholesale system only on an emergency basis or receiving only a small percentage and small volume of water from a wholesale system. The State may also determine that the combined distribution system does not include ce rtain wholesale systems based on factors such as delivering water to a consecutive system only on an emergency basis or delivering only a small percentage and small volume of water to a consecutive system.

(d) You must conduct standard monitoring that meets th e requirements in §141.601, or a system specific study that meets the requirements in §141.602, or ce rtify to the State that you meet 40/30 certification criteria under §141.603, or qualify for a very small system waiver under §141.604.
(1) You must have taken the full complement of routine TTHM and HAA5 compliance samples required of a system with your population and source water under subpart L of this part (or you must have taken the full complement of reduced TTHM and HAA5 compliance samples required of a system with your population and source water under subpart L if you m eet reduced monitoring criteria under subpart L of this part) during the period specified in §141.603(a) to meet the 40/30 certification criteria in §141.603. You must have taken TTHM and HAA5 samples under §§141.131 and 141.132 to be eligible for the very small system waiver in §141.604.

(2) If you have not taken the required samples, you must conduct standard monitoring that meets the requirements in §141.601, or a system specific study that meets the requirements in §141.602.
(e) You must use only the analytic al methods specified in §141.131, or otherwise approved by EPA for monitoring under this subpart, to demonstrate compliance with the requirements of this subpart.
(f) IDSE results will not be used for the purpos e of determining compliance with MCLs in §141.64.


### § 141.601 Standard monitoring.

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(a) Standard monitoring plan. Your standard monitoring plan must comply with paragraphs (a)(1) through (a)(4) of this section. You must prepare an d submit your standard monitoring plan to the State according to the schedule in §141.600(c).

(1) Your standard monitoring plan must include a sc hematic of your distribution system (including distribution system entry points and their sources, and storage facilities), with notes indicating locations and dates of all projected standard monitoring, an d all projected subpart L compliance monitoring.
(2) Your standard monitoring plan must include justific ation of standard monitoring location selection and a summary of data you relied on to justify standard monitoring location selection.
(3) Your standard monitoring plan must specify the population served and system type (subpart H or ground water).
(4) You must retain a complete copy of your s tandard monitoring plan submitted under this paragraph (a), including any State modification of your standard monitoring plan, for as long as you are required to retain your IDSE report under paragraph (c)(4) of this section.

(b) Standard monitoring. (1) You must monitor as indicated in the table in this paragraph (b)(1). You must collect dual sample sets at each monitoring lo cation. One sample in the dual sample set must be analyzed for TTHM. The other sample in the dual sample set must be analyzed for HAA5. You must conduct one monitoring period during the peak historical month for TTHM levels or HAA5 levels or the month of warmest water temperature. You must review available compliance, study, or operational data to determine the peak historical month for TTHM or HAA5 levels or warmest water temperature. 

## 49,999 2009 (iv) <10,000 (CWS Only) April 1, 2008 March 31, 2010 July 1, 2010.
Other systems that are part of a combined distribution system (v) Wholesale system or consecutive system —at the same time as the system with the earliest compliance date in the combined distribution system —at the same time as the system with the earliest compliance date in the combined distribution system —at the same time as the system with the earliest compliance date in the combined distribution system.

Source Population Monitoring periods

and frequency Distribution system monitoring locations 1



## Total per Near Average High High 

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...1 A dual sample set ( i.e. , a TTHM and an HAA5 sample) must be taken at each monitoring location during each monitoring period.

2 The peak historical month is the month with the high est TTHM or HAA5 levels or the warmest water temperature.
(2) You must take samples at locations other than the existing subpart L monitor ing locations. Monitoring locations must be distributed throughout the distribution system.
(3) If the number of entry points to the distribution syst em is fewer than the specified number of entry point monitoring locations, excess entry point sample s must be replaced equally at high TTHM and HAA5 locations. If there is an odd extra location number, you must take a sample at a high TTHM location. If the number of entry points to the distribution system is more than the specified number of entry point monitoring locations, y ou must take samples at entry points to the distribution system having the highest annual water flows.
(4) Your monitoring under this paragraph (b) may n ot be reduced under the provisions of §141.29 and the State may not reduce your monitori ng using the provisions of §142.16(m).
(c) IDSE report. Your IDSE report must include the elements re quired in paragraphs (c)(1) through (c)(4) of this section. You must submit your IDSE report to the State according to the schedule in §141.600(c).

(1) Your IDSE report must include all TTHM and HAA5 analytical results from subpart L compliance monitoring and all standard monitoring conducted during the period of the ID SE as individual analytical results and LRAAs presented in a tabular or sp readsheet format acceptable to the State. If changed from your standard monitoring plan submitted under par agraph (a) of this section, your report must also include a schematic of your distri bution system, the population serve d, and system type (subpart H or ground water).

(2) Your IDSE report must include an explanation of any deviations from your approved standard monitoring plan.



## water type size category of sampling monitoring period entry points residence time TTHM locations HAA5 locations Subpart H <500 consecutive systems one (during peak historical month) 2 

## 21 1

<500 nonconsecutive systems 2 11

500–3,300 consecutive systems four (every 90 days) 21 1

500–3,300nonconsecutive systems 2 11

3,301– 9,999 4 121
10,000– 49,999 six (every 60 days) 81 2 3 2
50,000– 249,999 16 3 4 5 4
250,000– 999,999 24 4 6 8 6
1,000,000– 4,999,999 32 6 8 10 8

≥ 5,000,000 40 8 10 12 10 Ground Water <500 consecutive systems one (during peak historical month) 2 

## 21 1

<500 nonconsecutive systems 2 11

500–9,999 four (every 90 days) 2 11
10,000– 99,999 61 1 2 2
100,000– 499,999 81 1 3 3

≥ 500,000 12 2 2 4 4 

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...(3) You must recommend and justify subpart V compliance monitoring locations and timing based on the protocol in §141.605.

(4) You must retain a complete copy of your IDSE report submitted under this section for 10 years after the date that you submitted your report. If the Sta te modifies the subpart V mo nitoring requirements that you recommended in your IDSE report or if the State approves alternative monitoring locations, you must keep a copy of the State's notific ation on file for 10 years after the date of the State's notification. You must make the IDSE report and any State notificati on available for review by the State or the public.


### § 141.602 System specific studies.

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(a) System specific study plan. Your system specific study plan must be based on either existing monitoring results as required under paragraph (a)(1) of this section or modeling as required under paragraph (a)(2) of this section. You must prepare and submit your system specific study plan to the State according to the schedule in §141.600(c).
(1) Existing monitoring results. You may comply by submitting monitoring results collected before you are required to begin monitoring under §141.600(c). The monitoring results and analysis must meet the criteria in paragraphs (a)(1)(i) and (a)(1)(ii) of this section.
(i) Minimum requirements. (A) TTHM and HAA5 results must be based on samples collected and analyzed in accordance with §141.131. Samples must be collected no earlier than five years prior to the study plan submission date.
(B) The monitoring locations and frequency must meet the conditions identified in this paragraph (a)(1)(i) (B). Each location must be sampled once during the peak historical month for TTHM levels or HAA5 levels or the month of warmest water temperature for every 12 months of data submitted for that location. Monitoring results must include all subpart L compliance monitoring re sults plus additional monitoring results as necessary to meet minimum sample requirements.

(ii) Reporting monitoring results. You must report the information in this paragraph (a)(1)(ii).
(A) You must report previously collected monitoring results and certify that the reported monitoring results include all compliance and non-compliance results generated during the time period beginning with the first reported result and ending with the most recent subpart L results.
(B) You must certify that the samples were representative of the entire distribution system and that treatment, and distribution system have not changed significantly since the samples were collected.

(C) Your study monitoring plan must include a sc hematic of your distribution system (including distribution system entry points and their sources, an d storage facilities), with notes indicating the locations and dates of all completed or pl anned system specific study monitoring.

(D) Your system specific study plan must specify the population served and system type (subpart H or ground water).
(E) You must retain a complete copy of your system specific study plan submitted under this paragraph (a)(1), including any State modification of your system specific study plan, for as long as you are required to retain your IDSE report under paragraph (b)(5) of this section.
(F) If you submit previously collected data that fully meet the number of samples required under paragraph (a)(1)(i)(B) of this section and the State rejects some of the data, you must either conduct additional monitoring to replace rejected data on a schedule the State approves or conduct standard monitoring under §141.601.
(2) Modeling. You may comply through analysis of an extended period simulation hydraulic model. The extended period simulation hydraulic model and analysis must meet the criteria in this paragraph (a)(2).

(i) Minimum requirements. (A) The model must simulate 24 hour variation in demand and show a consistently repeating 24 hour pattern of residence time. 

## System

Type Population size category Number of monitoring locations Number of samples TTHM HAA5 Subpart H: <500 3 3 3 500–3,300 3 9 9 3,301–9,999 6 36 36 10,000–49,999 12 72 72 50,000–249,999 24 144 144 250,000–999,999 36 216 216 1,000,000– 4,999,999 48 288 288

≥ 5,000,000 60 360 360 Ground Water: <500 3 3 3 500–9,999 3 9 9 10,000–99,999 12 48 48 100,000–499,999 18 72 72 ≥ 500,000 24 96 96 

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...(B) The model must represent the criteria listed in paragraphs (a)(2)(i)(B)(1) through (9) of this section.
(1) 75% of pipe volume;
(2) 50% of pipe length;
(3) All pressure zones;

(4) All 12-inch diameter and larger pipes;
(5) All 8-inch and larger pipes that connect pressure zones, influence zones from different sources, storage facilities, major demand areas, pumps, and co ntrol valves, or are known or expected to be significant conveyors of water;
(6) All 6-inch and larger pipes that connect remote areas of a distribution system to the main portion of the system;
(7) All storage facilities with standard operations represented in the model; and
(8) All active pump stations with co ntrols represented in the model; and
(9) All active control valves.
(C) The model must be calibrated, or have calibration plans, for the current configuration of the distribution system during the period of high TTHM formation potential. All storage facilities must be evaluated as part of the calibration process. All required calibration must be completed no later than 12 months after plan submission.

(ii) Reporting modeling. Your system specific study plan must in clude the information in this paragraph (a)(2)(ii).

(A) Tabular or spreadsheet data demonstrating that the mo del meets requirements in paragraph (a)(2)(i) (B) of this section.
(B) A description of all calibrati on activities undertaken, and if calibration is complete, a graph of predicted tank levels versus measured tank levels for the storage facility with the highest residence time in each pressure zone, and a time series grap h of the residence time at the longest residence time storage facility in the distribution system showing the predictions for the enti re simulation period ( i.e.
, from time zero until the time it takes to for the model to reach a consistently repeating pattern of residence time).
(C) Model output showing preliminary 24 hour av erage residence time predictions throughout the distribution system.
(D) Timing and number of samples representative of the distribution system planned for at least one monitoring period of TTHM and HAA5 dual sample monitoring at a number of locations no less than would be required for the system under standard monitori ng in §141.601 during the historical month of high TTHM. These samples must be taken at loc ations other than existing subpart L compliance monitoring locations.
(E) Description of how all requirements will be compl eted no later than 12 months after you submit your system specific study plan.

(F) Schematic of your distribution system (including distribution syst em entry points and their sources, and storage facilities), with notes indicating the locations and dates of all completed system specific study monitoring (if calibration is complete) and all subpart L compliance monitoring.

(G) Population served and system type (subpart H or ground water).
(H) You must retain a complete copy of your syste m specific study plan su bmitted under this paragraph (a)(2), including any State modification of your system specific study plan, for as long as you are required to retain your IDSE report under paragraph (b)(7) of this section.
(iii) If you submit a model that does not fully meet the requirements under paragraph (a)(2) of this section, you must correct the deficiencies and respond to State inquiries concerning the model. If you fail to correct deficiencies or respond to inquiries to the State's satisfaction, you must conduct standard monitoring under §141.601.
(b) IDSE report. Your IDSE report must include the elements re quired in paragraphs (b)(1) through (b)(6) of this section. You must submit your IDSE report according to the schedule in §141.600(c).
(1) Your IDSE report must include all TTHM and HAA5 analytical results from subpart L compliance monitoring and all system specific study monitoring co nducted during the period of the system specific study presented in a tabular or spreadsheet format acceptable to the State. If changed from your system specific study plan submitted under paragraph (a) of thi s section, your IDSE report must also include a schematic of your distribution system, the populati on served, and system type (subpart H or ground water).
(2) If you used the modeling provision under paragraph (a)(2) of this section, you must include final information for the elements described in paragraph (a)( 2)(ii) of this section, and a 24-hour time series graph of residence time for each subpart V compliance monitoring location selected.

(3) You must recommend and justify subpart V compliance monitoring locations and timing based on the protocol in §141.605.
(4) Your IDSE report must include an explanation of any deviations from your approved system specific study plan.
(5) Your IDSE report must include the basis (analytic al and modeling results) and justification you used to select the recommended subpart V monitoring locations.
(6) You may submit your IDSE report in lieu of your system specific study plan on the schedule identified 

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...in §141.600(c) for submission of the system specif ic study plan if you believe that you have the necessary information by the time that the system spec ific study plan is due. If you elect this approach, your IDSE report must also include all information required under paragraph (a) of this section.

(7) You must retain a complete copy of your IDSE report submitted under this section for 10 years after the date that you submitted your IDSE report. If the State modifies the subpart V monitoring requirements that you recommended in your IDSE reportor if the State approves alternative monitoring locations, you must keep a copy of the State's notific ation on file for 10 years after the date of the State's notification. You must make the IDSE report and any State notification available for review by the State or the public.


### § 141.603 40/30 certification.

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(a) Eligibility. You are eligible for 40/30 certification if you had no TTHM or HAA5 monitoring violations under subpart L of this part and no individual sample exceeded 0.040 mg/L for TTHM or 0.030 mg/L for HAA5 during an eight consecutive calendar quarter period beginning no earlier than the date specified in this paragraph (a).

1 Unless you are on reduced monitoring under subpart L of this part and were not required to monitor during the specified period. If you did not monitor during the specifi ed period, you must base your eligibility on compliance samples taken during the 12 months preceding the specified period.
(b) 40/30 certification. (1) You must certify to your State that every individual compliance sample taken under subpart L of this part during the periods specified in paragraph (a) of this section were ≤ 0.040 mg/L for TTHM and ≤ 0.030 mg/L for HAA5, and that you have not had any TTHM or HAA5 monitoring violations during the period specified in paragraph (a) of this section.
(2) The State may require you to submit compliance monitoring results, distribution system schematics, and/or recommended subpart V compliance monitoring loc ations in addition to your certification. If you fail to submit the requested information, the State ma y require standard monitoring under §141.601 or a system specific study under §141.602.
(3) The State may still require standard monitoring under §141.601 or a system specific study under §141.602 even if you meet the criteria in paragraph (a) of this section.

(4) You must retain a complete copy of your cert ification submitted under this section for 10 years after the date that you submitted your certification. You must make the certification, all data upon which the certification is based, and any State notification available for review by the State or the public.


### § 141.604 Very small system waivers.

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(a) If you serve fewer than 500 people and you have taken TTHM and HAA5 samples under subpart L of this part, you are not required to comply with this subpart unless the State notifies you that you must conduct standard monitoring under §141.601 or a system specific study under §141.602.
(b) If you have not taken TTHM and HAA5 samples undersubpart L of this part or if the State notifies you that you must comply with this subpart, you mustconduct standard monitoring under §141.601 or a system specific study under §141.602.


### § 141.605 Subpart V compliance monitoring location recommendations.

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(a) Your IDSE report must include your recommendations and justification for where and during what month(s) TTHM and HAA5 monitoring for subpart V of this part should be conducted. You must base your recommendations on the criteria in paragraphs (b) through (e) of this section.
(b) You must select the number of monitoring location s specified in the table in this paragraph (b). You will use these recommended locati ons as subpart V routine complianc e monitoring locations, unless State requires different or additional locations. You s hould distribute locations throughout the distribution system to the extent possible. 

## If your 40/30 certification is due Then your eligibility for 40/30 certification is based on eight consecutive calendar quarters of subpart L compliance monitoring results beginning no earlier than 1 

## (1) October 1, 2006 January 2004.
(2) April 1, 2007 January 2004. (3) October 1, 2007 January 2005.
(4) April 1, 2008 January 2005.

Source water type Population size category Monitoring frequency 1 

## Distribution system monitoring location
Total per monitoring

period 2 

## Highest TTHM locations Highest HAA5 locations Existing subpart L compliance

locations Subpart H: 

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...1 All systems must monitor during month of highest DBP concentrations.

2 Systems on quarterly monitoring must take dual samp le sets every 90 days at each monitoring location, except for subpart H systems serving 500–3,300. Ground water systems serving 500–9,999 on annual monitoring must take dual sample sets at each monitoring location. All other systems on annual monitoring and subpart H systems serving 500–3,300 are required to take individual TTHM and HAA5 samples (instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. For systems serving fewer than 500 people, only one location with a dual sample set per monitoring period is needed if the highest TTHM and HAA5 c oncentrations occur at the same location and month.
(c) You must recommend subpart V compliance m onitoring locations based on standard monitoring results, system specific study results, and subpart L compliance monitoring results. You must follow the protocol in paragraphs (c)(1) through (c)(8) of thi s section. If required to monitor at more than eight locations, you must repeat the protocol as necessary. If you do not have existing subpart L compliance monitoring results or if you do not have enough existing subpart L compliance monitoring results, you must repeat the protocol, skipping the provisions of paragraphs (c)(3) and (c)(7) of this section as necessary, until you have identified the requ ired total number of monitoring locations.
(1) Location with the highest TTHM LRAA not previous ly selected as a subpart V monitoring location.
(2) Location with the highest HAA5 LRAA not previously selected as a subpart V monitoring location.
(3) Existing subpart L average reside nce time compliance monitoring lo cation (maximum residence time compliance monitoring location for ground water systems) with the highest HAA5 LRAA not previously selected as a subpart V monitoring location.
(4) Location with the highest TTHM LRAA not previous ly selected as a subpart V monitoring location.
(5) Location with the highest TTHM LRAA not previous ly selected as a subpart V monitoring location.
(6) Location with the highest HAA5 LRAA not previously selected as a subpart V monitoring location.
(7) Existing subpart L average reside nce time compliance monitoring lo cation (maximum residence time compliance monitoring location for ground water systems) with the highest TTHM LRAA not previously selected as a subpart V monitoring location.
(8) Location with the highest HAA5 LRAA not previously selected as a subpart V monitoring location.
(d) You may recommend locations other than those spec ified in paragraph (c) of this section if you include a rationale for selecting other locations. If th e State approves the alternate locations, you must monitor at these locations to determine compliance under subpart V of this part.

(e) Your recommended schedule must include subpart V monitoring during the peakhistorical month for TTHM and HAA5 concentration, unless the State approve s another month. Once you have identified the peak historical month, and if you are required to conduct routine monitoring at least quarterly, you must schedule subpart V compliance monitoring at a regular frequency of every 90 days or fewer.

[71 FR 483, Jan. 4, 2006, as amended at 74 FR 30958, June 29, 2009]


### Subpart V—Stage 2 Disinfection Byproducts Requirements

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### Source: 71 FR 488, Jan. 4, 2006, unless otherwise noted.
§ 141.620 General requirements. 

## <500 per year 2 1 1 500–3,300 per quarter 2 1 1 3,301– 9,999 per quarter 2 1 1
10,000– 49,999 per quarter 4 2 1 1
50,000– 249,999 per quarter 8 3 3 2
250,000– 999,999 per quarter 12 5 4 3
1,000,000– 4,999,999 per quarter 16 6 6 4

≥ 5,000,000 per quarter 20 8 7 5 Ground water: <500 per year 2 1 1 500–9,999 per year 2 1 1 10,000– 99,999 per quarter 4 2 1 1
100,000– 499,999 per quarter 6 3 2 1

≥ 500,000 per quarter 8 3 3 2 

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(a) General. The requirements of subpart V of this part constitute national primary drinking water regulations. The regulations in this subpart estab lish monitoring and other r equirements for achieving compliance with maximum contaminant levels based on locational running annual averages (LRAA) for total trihalomethanes (TTHM) and haloacetic acids (five)(HAA5), and for achieving compliance with maximum residual disinfectant residuals for chlorine and chloramine for certain consecutive systems.
(b) Applicability. You are subject to thes e requirements if your system is a community water system or a nontransient noncommunity water system that uses a primary or residual disinfectant other than ultraviolet light or delivers water that has been tr eated with a primary or residual disinfectant other than ultraviolet light.
(c) Schedule. You must comply with the requirements in this subpart on the schedule in the following table based on your system type.

1 The State may grant up to an additional 24 month s for compliance with MCLs and operational evaluation levels if you require capital improvements to comply with an MCL.
(6) Your monitoring frequency is specified in §141.621(a)(2).
(i) If you are required to conduct quarterly monitoring, yo u must begin monitoring in the first full calendar quarter that includes the compliance date in the table in this paragraph (c).

(ii) If you are required to conduct monitoring at a fr equency that is less than quarterly, you must begin monitoring in the calendar month recommended in the IDSE report prepared under §141.601 or §141.602 or the calendar month identified in the subpart V monitoring plan developed under §141.622 no later than 12 months after the compliance date in this table.

(7) If you are required to conduct quarterly monitorin g, you must make compliance calculations at the end of the fourth calendar quarter that follows the compliance date and at the end of each subsequent quarter (or earlier if the LRAA calculated based on fewer than four quarters of data would cause the MCL to be exceeded regardless of the monitoring results of subsequent quarters). If you are required to conduct monitoring at a frequency that is less than quarterly, you must make compliance calculations beginning with the first compliance sample taken after the compliance date.

(8) For the purpose of the schedule in this paragraph (c), the State may determine that the combined distribution system does not include certain consec utive systems based on factors such as receiving water from a wholesale system only on an emergency basis or receiving only a small percentage and small volume of water from a wholesale system. The State may also determine that the combined distribution system does not include certain wholesale systems based on factors such as delivering water to a consecutive system only on an emergen cy basis or delivering only a small percentage and small volume of water to a consecutive system.
(d) Monitoring and compliance —(1) Systems required to monitor quarterly. To comply with subpart V MCLs in §141.64(b)(2), you must calculate LRAAs for TTHM and HAA5 using monitoring results collected under this subpart and determine that each LRAA does not exceed the MCL. If you fail to complete four consecutive quarters of monitoring, you must calculate compliance with the MCL based on the average of the available data from the mo st recent four quarters. If you take more than one sample per quarter at a monitoring location, you mu st average all samples taken in the quarter at that location to determine a quarterly average to be used in the LRAA calculation.
(2) Systems required to monitor yearly or less frequently. To determine compliance with subpart V MCLs in §141.64(b)(2), you must determine that each sample taken is less than the MCL. If any sample exceeds the MCL, you must comply with the requirements of §141.625. If no sample exceeds the MCL, the sample result for each monitoring location is considered the LRAA for that monitoring location.
(e) Violation. You are in violation of the monitoring requirements for each quarter that a monitoring result would be used in calculating an LRAA if you fail to monitor.

[71 FR 488, Jan. 4, 2006; 71 FR 4645, Jan. 27, 2006]


### § 141.621 Routine monitoring.

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## If you are this type of system You must comply with subpart V monitoring by: 1 

## Systems that are not part of a combined distribution system and systems that serve the largest population in the combined distribution system (1) System serving ≥ 100,000 April 1, 2012.
(2) System serving 50,000–99,999 October 1, 2012.
(3) System serving 10,000–49,999 October 1, 2013.
(4) System serving < 10,000 October 1, 2013 if no Cryptosporidiummonitoring is required under §141.701(a)(4) or October 1, 2014 if Cryptosporidiummonitoring is required under §141.701(a)(4) or (a)(6) Other systems that are part of a combined distribution system (5) Consecutive system or wholesale system —at the same time as the system with the earliest compliance date in the combined distribution system. 

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...(a) Monitoring. (1) If you submitted an IDSE report, you must begin monitoring at the locations and months you have recommended in your IDSE report submitted under §141.605 following the schedule in §141.620(c), unless the State requires other location s or additional locations after its review. If you submitted a 40/30 certification under §141.603 or you qu alified for a very small system waiver under §141.604 or you are a nontransient noncommunity water system serving <10,000, you must monitor at the location(s) and dates identified in your moni toring plan in §141.132(f), updated as required by §141.622.
(2) You must monitor at no fewer than the number of locations identified in this paragraph (a)(2).

1 All systems must monitor during month of highest DBP concentrations.

2 Systems on quarterly monitoring must take dual samp le sets every 90 days at each monitoring location, except for subpart H systems serving 500–3,300. Ground water systems serving 500–9,999 on annual monitoring must take dual sample sets at each monitoring location. All other systems on annual monitoring and subpart H systems serving 500–3,300 are required to take individual TTHM and HAA5 samples (instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. For systems serving fewer than 500 people, only one location with a dual sample set per monitoring period is needed if the highest TTHM and HAA5 c oncentrations occur at the same location and month.
(3) If you are an undisinfected system that begins us ing a disinfectant other than UV light after the dates in subpart U of this part for complying with the Initia l Distribution System Eval uation requirements, you must consult with the State to identify compliance m onitoring locations for this subpart. You must then develop a monitoring plan under §141.622 that includes those monitoring locations.

(b) Analytical methods. You must use an approved method listed in §141.131 for TTHM and HAA5 analyses in this subpart. Analyses must be conducted by l aboratories that have received certification by EPA or the State as specified in §141.131.

[71 FR 488, Jan. 4, 2006, as amended at 74 FR 30958, June 29, 2009]


### § 141.622 Subpart V monitoring plan.

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(a)(1) You must develop and implement a monitoring pl an to be kept on file for State and public review. The monitoring plan must contain the elements in paragraphs (a)(1)(i) through (a)(1)(iv) of this section and be complete no later than the date you conduc t your initial monitoring under this subpart.
(i) Monitoring locations;

(ii) Monitoring dates;
(iii) Compliance calcul ation procedures; and
(iv) Monitoring plans for any other systems in the co mbined distribution system if the State has reduced monitoring requirements under th e State authority in §142.16(m).

(2) If you were not required to submit an IDSE report under either §141.601 or §141.602, and you do not have sufficient subpart L monitoring locations to identify the required number of subpart V compliance monitoring locations indicated in §141.605(b), you must identify additional lo cations by alternating selection of locations representing high TTHM levels and high HAA5 levels until the required number of compliance monitoring locations have been identified. You must also provide the rationale for identifying the locations as having high levels of TTHM or HAA5. If you have more subpart L monitoring locations than required for subpart V compliance monitoring in §141.605(b), you must identi fy which locations you will use for subpart V compliance monitoring by alternating selection of locations representing high TTHM levels and high HAA5 levels until the required number of subpart V compliance monitoring locations have been identified.



## Source water type Population size category Monitoring Frequency 1 

## Distribution system monitoring location total per monitoring period 2 

## Subpart H: <500 per year 2 500–3,300 per quarter 2 3,301–9,999 per quarter 2 10,000–49,999 per quarter 4 50,000–249,999 per quarter 8 250,000– 999,999 per quarter 12
1,000,000– 4,999,999 per quarter 16

≥ 5,000,000 per quarter 20 Ground Water: <500 per year 2 500–9,999 per year 2 10,000–99,999 per quarter 4 100,000– 499,999 per quarter 6

≥ 500,000 per quarter 8 

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...(b) If you are a subpart H system serving > 3,300 people, you must submit a copy of your monitoring plan to the State prior to the date you conduct your initial monitoring under this subpart, unless your IDSE report submitted under subpart U of this part cont ains all the information required by this section.

(c) You may revise your monitoring plan to reflect changes in treatment, distribution system operations and layout (including new service areas), or other factors that may affect TTHM or HAA5 formation, or for State-approved reasons, after consultation with the State regarding the need for changes and the appropriateness of changes. If you change monitoring lo cations, you must replace existing compliance monitoring locations with the lowest LRAA with new lo cations that reflect the current distribution system locations with expected high TTHM or HAA5 levels . The State may also require modifications in your monitoring plan. If you are a subpart H system serv ing > 3,300 people, you must submit a copy of your modified monitoring plan to the State prior to the date you are required to comply with the revised monitoring plan.


### § 141.623 Reduced monitoring.

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(a) You may reduce monitoring to the level specified in the table in this paragraph (a) any time the LRAA is ≤ 0.040 mg/L for TTHM and ≤ 0.030 mg/L for HAA5 at all monitoring locations. You may only use data collected under the provisions of this subpart or subpartL of this part to qualify for reduced monitoring. In addition, the source water annual average TOC level, before any treatment, must be ≤ 4.0 mg/L at each treatment plant treating surface water or ground water under the direct influence of surface water, based on monitoring conducted under ei ther §141.132(b)(1)(iii) or §141.132(d).



## Source water type Population size category Monitoring frequency 1 

## Distribution system monitoring location per monitoring period Subpart H: <500 monitoring may not be reduced. 500–3,300 per year 1 TTHM and 1 HAA5 sample: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement; 1 dual sample set per year if the highest TTHM and HAA5 measurements occurred at the same location and quarter. 3,301–9,999 per year 2 dual sample sets: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement. 10,000– 49,999 per quarter 2 dual sample sets at the locations with the highest TTHM and highest HAA5 LRAAs. 50,000– 249,999 per quarter 4 dual sample sets—at the locations with the two highest TTHM and two highest HAA5 LRAAs. 250,000– 999,999 per quarter 6 dual sample sets—at the locations with the three highest TTHM and three highest HAA5 LRAAs. 1,000,000– 4,999,999 per quarter 8 dual sample sets—at the locations with the four highest TTHM and four highest HAA5 LRAAs. ≥ 5,000,000 per quarter 10 dual sample sets—at the locations with the five highest TTHM and five highest HAA5 LRAAs. Ground Water: <500 every third year 1 TTHM and 1 HAA5 sample: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement; 1 dual sample set per year if the highest TTHM and HAA5 measurements occurred at the same location and quarter. 500–9,999 per year 1 TTHM and 1 HAA5 sample: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement; 1 dual sample set per year if the highest TTHM and HAA5 measurements 

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...1 Systems on quarterly monitoring must take dual sample sets every 90 days.

(b) You may remain on reduced monitoring as long as the TTHM LRAA ≤ 0.040 mg/L and the HAA5 LRAA ≤ 0.030 mg/L at each monitoring location (for sys tems with quarterly reduced monitoring) or each TTHM sample ≤ 0.060 mg/L and each HAA5 sample ≤ 0.045 mg/L (for systems with annual or less frequent monitoring). In addition, the source wate r annual average TOC level, before any treatment, must be ≤ 4.0 mg/L at each treatment plant treating surface water or ground water under the direct influence of surface water, based on monitoring conducted under either §141.132(b)(1)(iii) or §141.132 (d).

(c) If the LRAA based on quarterly monitoring at any m onitoring location exceeds either 0.040 mg/L for TTHM or 0.030 mg/L for HAA5 or if the annual (or less frequent) sample at any location exceeds either 0.060 mg/L for TTHM or 0.045 mg/L for HAA5, or if the source water annual average TOC level, before any treatment, >4.0 mg/L at any treatment plant treating surface water or ground water under the direct influence of surface water, you must resume routine monitoring under §141.621 or begin increased monitoring if §141.625 applies.
(d) The State may return your system to routine monitoring at the State's discretion.


### § 141.624 Additional requirements for consecutive systems.

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If you are a consecutive system that does not add a di sinfectant but delivers water that has been treated with a primary or residual disinfectant other than ul traviolet light, you must comply with analytical and monitoring requirements for chlorine and chlorami nes in §141.131 (c) and §141.132(c)(1) and the compliance requirements in §141.133(c)(1) beginni ng April 1, 2009, unless required earlier by the State, and report monitoring results under §141.134(c).


### § 141.625 Conditions requiring increased monitoring.

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(a) If you are required to monitor at a particular loc ation annually or less frequently than annually under §141.621 or §141.623, you must increase monitoring to du al sample sets once per quarter (taken every 90 days) at all locations if a TTHM sample is >0.080 mg/L or a HAA5 sample is >0.060 mg/L at any location.
(b) You are in violation of the MCL when the LRAA ex ceeds the subpart V MCLs in §141.64(b)(2), calculated based on four consecutive quarters of monitoring (or the LRAA calculated based on fewer than four quarters of data if the MCL would be exceeded regardless of the monitoring results of subsequent quarters). You are in violation of the monitoring requirements for each quarter that a monitoring result would be used in ca lculating an LRAA if you fail to monitor.

(c) You may return to routine monitoring once you have conducted increased monitoring for at least four consecutive quarters and the LRAA fo r every monitoring location is ≤ 0.060 mg/L for TTHM and ≤ 0.045 mg/L for HAA5.


### § 141.626 Operational evaluation levels.

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(a) You have exceeded the operational evaluation leve l at any monitoring location where the sum of the two previous quarters' TTHM results plus twice the current quarter's TTHM result, divided by 4 to determine an average, exceeds 0.080 mg/L, or where the sum of the two previous quarters' HAA5 results plus twice the current quarter's HAA5 resu lt, divided by 4 to determine an average, exceeds 0.060 mg/L.
(b)(1) If you exceed the operational evaluation level, you must conduct an operational evaluation and submit a written report of the evaluation to the State no later than 90 days after being notified of the analytical result that causes you to exceed the operational evaluation level. The written report must be made available to the public upon request.
(2) Your operational evaluation must include an examination of system treatment and distribution operational practices, including s torage tank operations, excess storage capacity, distribution system flushing, changes in sources or source water quality, and treatment changes or problems that may contribute to TTHM and HAA5 formation and what steps could be considered to minimize future exceedences.
(i) You may request and the State may allow you to limi t the scope of your evaluation if you are able to identify the cause of the operat ional evaluation level exceedance.
(ii) Your request to limit the scop e of the evaluation does not extend t he schedule in paragraph (b)(1) of 

## occurred at the same location and quarter. 10,000– 99,999 per year 2 dual sample sets: one at the location and during the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement. 100,000– 499,999 per quarter 2 dual sample sets; at the locations with the highest TTHM and highest HAA5 LRAAs. ≥ 500,000 per quarter 4 dual sample sets at the locations with the two highest TTHM and two highest HAA5 LRAAs. 

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...this section for submitting the written report. The State must approve this limited scope of evaluation in writing and you must keep that approval with the completed report.


### § 141.627 Requirements for remaining on reduced TTHM and HAA5 monitoring based on subpart L results.

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You may remain on reduced monitoring after the dates identified in §141.620(c) for compliance with this subpart only if you qualify for a 40/30 certification under §141.603 or have received a very small system waiver under §141.604, plus you meet the reduced monitoring criteria in §141.623(a), and you do not change or add monitoring locations from those used for compliance monitoring under subpart L of this part. If your monitoring locations under this subpart differ from your monitoring locations under subpart L of this part, you may not remain on reduced moni toring after the dates identified in §141.620(c) for compliance with this subpart.


### § 141.628 Requirements for remaining on increased TTHM and HAA5 monitoring based on subpart L results.

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If you were on increased monitoring under §141.132(b)(1), you must remain on increased monitoring until you qualify for a return to routine monitori ng under §141.625(c). You must conduct increased monitoring under §141.625 at the monitoring locations in the monitoring plan developed under §141.622 beginning at the date identified in §141.620(c) for comp liance with this subpart and remain on increased monitoring until you qualify for a return to routine monitoring under §141.625(c).


### § 141.629 Reporting and recordkeeping requirements.

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(a) Reporting. (1) You must report the following information for each monitoring location to the State within 10 days of the end of any quarter in which monitoring is required:

(i) Number of samples taken during the last quarter.
(ii) Date and results of each sample taken during the last quarter.
(iii) Arithmetic average of quarterly results for the last four quarters for each monitoring location (LRAA), beginning at the end of the fourth calendar quarter that follows the compliance date and at the end of each subsequent quarter. If the LRAA calculated based on fewer than four quarters of data would cause the MCL to be exceeded regardless of the monitoring results of subsequent quarters, you must report this information to the State as part of the first report due following the compliance date or anytime thereafter that this determination is made. If you are required to conduct monitoring at a frequency that is less than quarterly, you must make compliance calculations beginning with the first compliance sample taken after the compliance date, unless you are required to conduct increased monitoring under §141.625.
(iv) Whether, based on §141.64(b)(2) and this subpart, the MCL was violated at any monitoring location.
(v) Any operational evaluation leve ls that were exceeded during the quarter and, if so, the location and date, and the calculated TTHM and HAA5 levels.
(2) If you are a subpart H system seeking to qualifyfor or remain on reduced TTHM/HAA5 monitoring, you must report the following source water TOC info rmation for each treatment plant that treats surface water or ground water under the direct influence of surface water to the State within 10 days of the end of any quarter in which monitoring is required:
(i) The number of source water TOC samples taken each month during last quarter.
(ii) The date and result of each sample taken during last quarter.
(iii) The quarterly average of monthly samples taken during last quarter or the result of the quarterly sample.
(iv) The running annual average (RAA) of quarte rly averages from the past four quarters.
(v) Whether the RAA exceeded 4.0 mg/L.
(3) The State may choose to perform calculations and determine whether the MCL was exceeded or the system is eligible for reduce d monitoring in lieu of having the system report that information

(b) Recordkeeping. You must retain any subpart V monitoring plans and your subpart V monitoring results as required by §141.33.


### Subpart W—Enhanced Treatment forCryptosporidium

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### Source: 71 FR 769, Jan. 5, 2006, unless otherwise noted.
General Requirements

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### § 141.700 General requirements. 

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(a) The requirements of this subpart W are national primary drinking water regulations. The regulations in this subpart establish or extend treatment techn ique requirements in lieu of maximum contaminant levels for Cryptosporidium. These requirements are in addition to requirements for filtration and disinfection in subparts H, P, and T of this part.
(b) Applicability. The requirements of this subpart apply to al l subpart H systems, which are public water systems supplied by a surface water source and public water systems supplied by a ground water source under the direct influence of surface water.
(1) Wholesale systems, as defined in §141.2, must comp ly with the requirements of this subpart based on the population of the largest system in the combined distribution system.

(2) The requirements of this subpart for filtered syste ms apply to systems required by National Primary Drinking Water Regulations to provide filtration treatment, whether or not the system is currently operating a filtration system.

(3) The requirements of this subpart for unfiltered sys tems apply only to unfiltered systems that timely met and continue to meet the filtration avoidance crit eria in subparts H, P, and T of this part, as applicable.
(c) Requirements. Systems subject to this subpart must comply with the following requirements:
(1) Systems must conduct an initial and a second ro und of source water monitoring for each plant that treats a surface water or GWUDI source. This monitoring may include sampling for Cryptosporidium, E. coli, and turbidity as described in §§141.701 through 141.706, to determine what level, if any, of additional Cryptosporidium treatment they must provide.
(2) Systems that plan to make a significant change to their disinfection practice must develop disinfection profiles and calculate di sinfection benchmarks, as descri bed in §§141.708 through 141.709.

(3) Filtered systems must determine their Cryptosporidium treatment bin classification as described in §141.710 and provide additional treatment for Cryptosporidium, if required, as described in §141.711. All unfiltered systems must provide treatment for Cryptosporidium as described in §141.712. Filtered and unfiltered systems must implement Cryptosporidium treatment according to the schedule in §141.713.

(4) Systems with uncovered finished water storage faci lities must comply with the requirements to cover the facility or treat the discharge from the facility as described in §141.714.
(5) Systems required to provide additional treatment for Cryptosporidium must implement microbial toolbox options that are designed and operated as described in §§141.715 through 141.720.
(6) Systems must comply with the applicable record keeping and reporting requirements described in §§141.721 through 141.722.
(7) Systems must address significant deficiencies identified in sanitary surveys performed by EPA as described in §141.723.


### Source Water Monitoring Requirements

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### § 141.701 Source water monitoring.

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(a) Initial round of source water monitoring. Systems must conduct the following monitoring on the schedule in paragraph (c) of this section unless theymeet the monitoring exemption criteria in paragraph (d) of this section.

(1) Filtered systems serving at least 10,000 people must sample their source water for Cryptosporidium, E. coli, and turbidity at least monthly for 24 months.
(2) Unfiltered systems serving at least 10,000 people must sample their source water for Cryptosporidium at least monthly for 24 months.
(3)(i) Filtered systems serving fewer than 10,000 people must sample their source water for E. coli at least once every two weeks for 12 months.
(ii) A filtered system serving few er than 10,000 people may avoid E. coli monitoring if the system notifies the State that it will monitor for Cryptosporidium as described in paragraph (a)(4) of this section. The system must notify the State no later than 3 months prior to the date the system is otherwise required to start E. coli monitoring under §141.701(c).

(4) Filtered systems serving fewer than 10,000 people must sample their source water for Cryptosporidium at least twice per month for 12 months or atleast monthly for 24 months if they meet one of the following, based on monitoring conducted under paragraph (a)(3) of this section:

(i) For systems using lake/reservoir sources, the annual mean E. coli concentration is greater than 10 E. coli /100 mL.
(ii) For systems using flowing stream sources, the annual mean E. coli concentration is greater than 50 E. coli /100 mL.
(iii) The system does not conduct E. coli monitoring as described in paragraph (a)(3) of this section.
(iv) Systems using ground water under the direct in fluence of surface water (GWUDI) must comply with the requirements of paragraph (a)(4) of this section based on the E. coli level that applies to the nearest 

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...surface water body. If no surface water body is nearby, the system must comply based on the requirements that apply to systems using lake/reservoir sources.

(5) For filtered systems serving fewer than 10,000 people, the State may approve monitoring for an indicator other than E. coli under paragraph (a)(3) of this section. The State also may approve an alternative to the E. coli concentration in paragraph (a)(4)(i), (ii) or (iv) of this section to trigger Cryptosporidium monitoring. This approval by the State mustbe provided to the system in writing and must include the basis for the State's determination that the alternative indicator and/or trigger level will provide a more accurate identi fication of whether a system will exceed the Bin 1 Cryptosporidium level in §141.710.

(6) Unfiltered systems serving fewer than 10,000 people must sample their source water for Cryptosporidium at least twice per month for 12 months or at least monthly for 24 months.
(7) Systems may sample more frequently than required under this section if the sampling frequency is evenly spaced throughout the monitoring period.
(b) Second round of source water monitoring. Systems must conduct a second round of source water monitoring that meets the requirements for monitoring parameters, frequency, and duration described in paragraph (a) of this section, unless they meet the monitoring exemption criteria in paragraph (d) of this section. Systems must conduct this monitoring on the schedule in paragraph (c) of this section.
(c) Monitoring schedule. Systems must begin the monitoring required in paragraphs (a) and (b) of this section no later than the month beginning with the date listed in this table:
Source Water Monitoring Starting Dates Table

a Applies only to filtered systems.

bApplies to filtered systems that meet the conditions of paragraph (a)(4) of this section and unfiltered systems.
(d) Monitoring avoidance. (1) Filtered systems are not required to conduct source water monitoring under this subpart if the system will provide a total of at least 5.5-log of treatment for Cryptosporidium, equivalent to meeting the treatment requirements of Bin 4 in §141.711.
(2) Unfiltered systems are not required to conduct source water monitoring under this subpart if the system will provide a total of at least 3-log Cryptosporidium inactivation, equivalent to meeting the treatment requirements for unfiltered systems with a mean Cryptosporidium concentration of greater than 0.01 oocysts/L in §141.712.
(3) If a system chooses to provide the level of treatment in paragraph (d)(1) or (2) of this section, as applicable, rather than start source water monitoring, the system mustnotify the State in writing no later than the date the system is otherwise required to su bmit a sampling schedule for monitoring under §141.702. Alternatively, a system may choose to stop sampling at any point after it has initiated monitoring if it notifies the State in writing that it will provide this level of treatment. Systems must install and operate technologies to provide this level of trea tment by the applicable treatment compliance date in §141.713.
(e) Plants operating only part of the year. Systems with subpart H plants that operate for only part of the year must conduct source water monitoring in ac cordance with this subpart, but with the following modifications:
(1) Systems must sample their source water only during the months that the plant operates unless the State specifies another monitoring period based on plant operating practices.
(2) Systems with plants that operate less th an six months per year and that monitor for Cryptosporidium must collect at least six Cryptosporidium samples per year during each of two years of monitoring. Samples must be evenly spaced th roughout the period the plant operates.
(f)(1) New sources. A system that begins using a new source of surface water or GWUDI after the system is required to begin monitoring under paragra ph (c) of this section must monitor the new source on a schedule the State approves. Source water moni toring must meet the requirements of this subpart. The system must also meetthe bin classification and Cryptosporidium treatment requirements of §§141.710 and 141.711 or §141.712, as applicable, for the new source on a schedule the State approves.
(2) The requirements of §141.701(f) apply to subpart H systems that begin operation after the monitoring start date applicable to the system's size under paragraph (c) of this section. 

## Systems that serve . .

. Must begin the first round of source water

monitoring no later

than the month beginning . . . And must begin the second round of source water monitoring no later than the month beginning . . . (1) At least 100,000 people (i) October 1, 2006 (ii) April 1, 2015.
(2) From 50,000 to 99,999 people (i) April 1, 2007 (ii) October 1, 2015.
(3) From 10,000 to 49,999 people (i) April 1, 2008 (ii) October 1, 2016.
(4) Fewer than 10,000 and monitor for E. coli
a 

## (i) October 1, 2008 (ii) October 1, 2017.

(5) Fewer than 10,000 and monitor for Cryptosporidium b 

## (i) April 1, 2010 (ii) April 1, 2019. 

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...(3) The system must begin a second round of source water monitoring no later than 6 years following initial bin classification under §141.710 or determination of the mean Cryptosporidium level under §141.712, as applicable.

(g) Failure to collect any source water sample re quired under this section in accordance with the sampling schedule, sampling location, analytic al method, approved laboratory, and reporting requirements of §§141.702 through 141 .706 is a monitoring violation.
(h) Grandfathering monitoring data. Systems may use (grandfather) monitoring data collected prior to the applicable monitoring start date in paragraph (c) of this section to meet the initial source water monitoring requirements in paragraph (a) of this section. Grandfathered data may substitute for an equivalent number of months at the end of the monitoring period. All data submitted under this paragraph must meet the requirements in §141.707.


### § 141.702 Sampling schedules.

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(a) Systems required to conduct source water monitoring under §141.701 must submit a sampling schedule that specifies the calendar dates when the system will collect each required sample.
(1) Systems must submit sampling schedules no later than 3 months prior to the applicable date listed in §141.701(c) for each round of required monitoring.
(2)(i) Systems serving at least 10,000 people must submit their sampling schedule for the initial round of source water monitoring under §141.701(a) to EPA electronically at https://intranet.epa.gov/lt2/.

(ii) If a system is unable to submit the sampling schedule electronically, the system may use an alternative approach for submitting the sampling schedule that EPA approves.
(3) Systems serving fewer than 10,000 people must s ubmit their sampling schedules for the initial round of source water monitoring §141.701(a) to the State.
(4) Systems must submit sampling schedules for the second round of source water monitoring §141.701 (b) to the State.
(5) If EPA or the State does not respond to a system regarding its sampling schedule, the system must sample at the reported schedule.
(b) Systems must collect samples within two days before or two days after the dates indicated in their sampling schedule ( i.e. , within a five-day period around the schedule date) unless one of the conditions of paragraph (b)(1) or (2) of this section applies.

(1) If an extreme condition or situati on exists that may pose danger to the sample collector, or that cannot be avoided and causes the sy stem to be unable to sample in the scheduled five-day period, the system must sample as close to the scheduled date as is feasible unless the State approves an alternative sampling date. The system must submit an explanation for the delayed sampling date to the State concurrent with the shipment of the sample to the laboratory.
(2)(i) If a system is unable to report a valid analytical result for a scheduled sampling date due to equipment failure, loss of or damage to the samp le, failure to comply with the analytical method requirements, including the quality control requirements in §141.704, or the failure of an approved laboratory to analyze the sample, then the system must collect a replacement sample.
(ii) The system must collect the replacement sample not later than 21 days after receiving information that an analytical result cannot be reported for the scheduled date unless the system demonstrates that collecting a replacement sample within this time frame is not feasible or the State approves an alternative resampling date. The system must submit an explanation for the delayed sampling date to the State concurrent with the shipment of the sample to the laboratory.
(c) Systems that fail to meet the criteria of paragra ph (b) of this section for any source water sample required under §141.701 must revise their samplin g schedules to add dates forcollecting all missed samples. Systems must submit the revised schedule to the State for approval prior to when the system begins collecting the missed samples.


### § 141.703 Sampling locations.

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(a) Systems required to conduct source water monitoring under §141.701 must collect samples for each plant that treats a surface water or GWUDI source. Where multiple plants draw water from the same influent, such as the same pipe or intake, the State may approve one set of monitoring results to be used to satisfy the requirements of §141.701 for all plants.
(b)(1) Systems must collect source water samples prior to chemical treatment, such as coagulants, oxidants and disinfectants, unless the system meets the condition of paragraph (b)(2) of this section.
(2) The State may approve a system to collect a source water sample after chemical treatment. To grant this approval, the State must determine that collecting a sample prior to chemical treatment is not feasible for the system and that the chemical treatment is unlikely to have a significant adverse effect on the analysis of the sample.
(c) Systems that recycle filter backwash water mustcollect source water samples prior to the point of filter backwash water addition.

(d) Bank filtration. (1) Systems that receive Cryptosporidium treatment credit for bank filtration under §141.173(b) or §141.552(a), as applicable, must collect source water samples in the surface water prior to bank filtration.

(2) Systems that use bank filtration as pretreatment to a filtration plant must collect source water samples from the well ( i.e. , after bank filtration). Use of bank filtration during monitoring must be 

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...consistent with routine operational practice. Systems collecting samples after a bank filtration process may not receive treatment credit for the bank filtration under §141.717(c).

(e) Multiple sources. Systems with plants that use multiple water sources, including multiple surface water sources and blended surface water and ground watersources, must collect samples as specified in paragraph (e)(1) or (2) of this section. The us e of multiple sources during monitoring must be consistent with routine operational practice.
(1) If a sampling tap is available where the source s are combined prior to treatment, systems must collect samples from the tap.
(2) If a sampling tap where the sources are combined prior to treatment is not av ailable, systems must collect samples at each source near the intake on the same day and must follow either paragraph (e)(2) (i) or (ii) of this section for sample analysis.
(i) Systems may composite samples from each source into one sample prior to analysis. The volume of sample from each source must be weighted according to the proportion of the source in the total plant flow at the time the sample is collected.
(ii) Systems may analyze samples from each sour ce separately and calculate a weighted average of the analysis results for each sampling date. The weigh ted average must be calculated by multiplying the analysis result for each source by the fraction the source contributed to total plant flow at the time the sample was collected and then summing these values.
(f) Additional Requirements. Systems must submit a description of their sampling location(s) to the State at the same time as the sampling schedule required under §141.702. This description must address the position of the sampling location in relation to the system's water source(s) and treatment processes, including pretreatment, points of chem ical treatment, and filter backwash recycle. If the State does not respond to a system regarding sampling location(s), the system must sample at the reported location(s).


### § 141.704 Analytical methods.

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(a) Cryptosporidium. Systems must analyze for Cryptosporidium using Method 1623: Cryptosporidium and Giardia in Water by Filtration/IMS/FA, 2005, United States Environmental Protection Agency, EPA– 815–R–05–002 or Method 1622: Cryptosporidium in Water by Filtration/IMS/FA, 2005, United States Environmental Protection Agency, EPA–815–R–05–001, which are incorporated by reference, or alternative methods listed in appendix A to subpart C of this part. The Director of the Federal Register approves this incorporation by reference in accor dance with 5 U.S.C. 552(a) and 1 CFR part 51. You may obtain a copy of these methods online from http://www.epa.gov/safewater/disinfection/lt2 or from the United States Environmental Protection Agency, Office of Ground Water and Drinking Water, 1201 Constitution Ave., NW., Washington, DC 20460 ( Telephone: 800–426–4791). You may inspect a copy at the Water Docket in the EPA Docket Center, 1301 Constitution Ave., NW., Washington, DC ( Telephone: 202–566–2426) or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202–741–6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html

. (1) Systems must analyze at least a 10 L sample or a packed pellet volume of at least 2 mL as generated by the methods listed in paragraph (a) of this section. Systems unable to process a 10 L sample must analyze as much sample volume as c an be filtered by two filters approved by EPA for the methods listed in paragraph (a) of this section, up to a packed pellet volume of at least 2 mL.
(2)(i) Matrix spike (MS) samples, as required by the methods in paragraph (a) of this section, must be spiked and filtered by a laboratory approved for Cryptosporidium analysis under §141.705.
(ii) If the volume of the MS sample is greater than 10 L, the system may filter all but 10 L of the MS sample in the field, and ship the filtered sample and the remaining 10 L of source water to the laboratory. In this case, the laboratory must spike the remaining 10 L of water and filter it through the filter used to collect the balance of the sample in the field.
(3) Flow cytometer-counted spiking suspensions must be used for MS samples and ongoing precision and recovery (OPR) samples.

(b) E. coli. System must use methods for enumeration of E. co li in source water approved in §136.3(a) of this chapter or alternative methods listed in appendix A to subpart C of this part.
(1) The time from sample collection to initiation of analysis may not exceed 30 hours unless the system meets the condition of paragraph (b)(2) of this section.
(2) The State may approve on a case-by-case basis the holding of an E. coli sample for up to 48 hours between sample collection and initiation of an alysis if the State determines that analyzing an E. coli sample within 30 hours is not feasible. E. coli samples held between 30 to 48 hours must be analyzed by the Colilert reagent version of Standard Method 9223B as listed in §136.3(a) of this title.
(3) Systems must maintain samples between 0 °C and 10 °C during storage and transit to the laboratory.
(c) Turbidity. Systems must use methods for turbiditymeasurement approved in §141.74(a)(1).

[71 FR 769, Jan. 5, 2006, as amended at 74 FR 30959, June 29, 2009]


### § 141.705 Approved laboratories.

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(a) Cryptosporidium. Systems must have Cryptosporidium samples analyzed by a laboratory that is approved under EPA's Laboratory Quality Assurance Evaluation Program for Analysis of Cryptosporidium in Water or a laboratory that has been certified for Cryptosporidium analysis by an equivalent State laboratory certification program.
(b) E. coli. Any laboratory certified by the EPA, the National Environmental Laboratory Accreditation 

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...Conference or the State for total coliform or feca l coliform analysis under §141.74 is approved for E. coli analysis under this subpart when the labo ratory uses the same technique for E. coli that the laboratory uses for §141.74.

(c) Turbidity. Measurements of turbidity must be ma de by a party approved by the State.


### § 141.706 Reporting source water monitoring results.

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(a) Systems must report results from the source water monitoring required under §141.701 no later than 10 days after the end of the first month following the month when the sample is collected.
(b)(1) All systems serving at least 10,000 people mustreport the results from the initial source water monitoring required under §141.701(a) to EPA electronically at https://intranet.epa.gov/lt2/.
(2) If a system is unable to report monitoring results el ectronically, the system may use an alternative approach for reporting monitoring results that EPA approves.

(c) Systems serving fewer than 10,000 people must report results from the initial source water monitoring required under §141.701(a) to the State.
(d) All systems must report results from the second round of source water monitoring required under §141.701(b) to the State.
(e) Systems must report the applicable information in paragraphs (e)(1) and (2) of this section for the source water monitoring required under §141.701.
(1) Systems must report the following data elements for each Cryptosporidium analysis:

(i) For matrix spike samples, systems must also report the sample volume spiked and estimated number of oocysts spiked. These data are not required for field samples.

(ii) For samples in which less than 10 L is filtered or less than 100% of the sample volume is examined, systems must also report the number of filters used and the packed pellet volume.
(iii) For samples in which less than 100% of sample vo lume is examined, systems must also report the volume of resuspended concentrate and volume of this resuspension processed through immunomagnetic separation.
(2) Systems must report the following data elements for each E. coli analysis:

1 Systems serving fewer than 10,000 people that are not required to monitor for turbidity under §141.701 are not required to report turbidity with their E. coli results.


### § 141.707 Grandfathering previously collected data.

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(a)(1) Systems may comply with the initial source water monitoring requirements of §141.701(a) by grandfathering sample results collected before the system is required to begin monitoring ( i.e.
, previously collected data). To be grandfathered, the samp le results and analysis must meet the criteria in this section and the State must approve.
(2) A filtered system may grandfather Cryptosporidium samples to meet the requirements of §141.701(a) when the system does not have corresponding E. coli and turbidity samples. A system that grandfathers Cryptosporidium samples without E. coli and turbidity samples is not required to collect E. coli and turbidity samples when the system completes the requirements for Cryptosporidium monitoring under §141.701(a).
(b) E. coli sample analysis. The analysis of E. coli samples must meet the analytical method and 

## Data element. 1. PWS ID. 2. Facility ID. 3. Sample collection date. 4. Sample type (field or matrix spike). 5. Sample volume filtered (L), to nearest 1/4 L. 6. Was 100% of filtered volume examined. 7. Number of oocysts counted.

Data element. 1. PWS ID. 2. Facility ID. 3. Sample collection date. 4. Analytical method number. 5. Method type. 6. Source type (flowing stream, lake/reservoir, GWUDI). 7. E. coli /100 mL. 8. Turbidity. 1 

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...approved laboratory requirements of §§141.704 through 141.705.
(c) Cryptosporidium sample analysis. The analysis of Cryptosporidium samples must meet the criteria in this paragraph.
(1) Laboratories analyzed Cryptosporidium samples using one of the analytical methods in paragraphs (c)(1)(i) through (vi) of this section, which are inco rporated by reference. The Director of the Federal Register approves this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. You may obtain a copy of these methods on-line from the United States Environmental Protection A gency, Office of Ground Water and Drinking Water, 1201 Constitution Ave, NW, Washington, DC 20460 (Telephone: 800–426–4791). You may inspect a copy at the Water Docket in the EPA Docket Center, 1301 Constitution Ave., NW , Washington, DC, (Telephone: 202–566–2426) or at the National A rchives and Records Administration (NARA). For in formation on the availability of this material at NARA, call 202–741–6030, or go to: http://www.archives.gov/federal_ r egister/code_of_federal_ regulations/ibr_locations.html.

(i) Method 1623: Cryptosporidium and Giardia in Water by Filtration/IMS/FA, 2005, United States Environmental Protection Agency, EPA–815–R–05–002.
(ii) Method 1622: Cryptosporidium in Water by Filtration/IMS/FA, 2005, United States Environmental Protection Agency, EPA–815–R–05–001.
(iii) Method 1623: Cryptosporidium and Giardia in Water by Filtration/IMS/FA, 2001, United States Environmental Protection Agency, EPA–821–R–01–025.
(iv) Method 1622: Cryptosporidium in Water by Filtration/IMS/FA, 2001, United States Environmental Protection Agency, EPA–821–-R–01–026.
(v) Method 1623: Cryptosporidium and Giardia in Water by Filtration/IMS/FA, 1999, United States Environmental Protection Agency, EPA–821–R–99–006.
(vi) Method 1622: Cryptosporidium in Water by Filtration/IMS/FA, 1999, United States Environmental Protection Agency, EPA–821–R–99–001.
(2) For each Cryptosporidium sample, the laboratory analyzed at least 10 L of sample or at least 2 mL of packed pellet or as much volume as could be filtered by 2 filters that EPA approved for the methods listed in paragraph (c)(1) of this section.
(d) Sampling location. The sampling location must meet the conditions in §141.703.

(e) Sampling frequency. Cryptosporidium samples were collected no less frequently than each calendar month on a regular schedule, beginning no earlier tha n January 1999. Sample collection intervals may vary for the conditions specified in §141.702(b)(1) and (2) if the system provides documentation of the condition when reporting monitoring results.
(1) The State may approve grandfathering of previouslycollected data where there are time gaps in the sampling frequency if the system conducts additional monitoring the State specifies to ensure that the data used to comply with the initial source water monitoring requirements of §141.701(a) are seasonally representative and unbiased.
(2) Systems may grandfather previously collected data where the sampling frequency within each month varied. If the Cryptosporidium sampling frequency varied, systems must follow the monthly averaging procedure in §141.710(b)(5) or §141.712(a)(3), as applic able, when calculating the bin classification for filtered systems or the mean Cryptosporidium concentration for unfiltered systems.
(f) Reporting monitoring results for grandfathering. Systems that request to grandfather previously collected monitoring results must report the following i nformation by the applicable dates listed in this paragraph. Systems serving at least 10,000 people mu st report this information to EPA unless the State approves reporting to the State rather than EPA. Sys tems serving fewer than 10,000 people must report this information to the State.
(1) Systems must report that they intend to subm it previously collected monitoring results for grandfathering. This report must specify the number of previously collected results the system will submit, the dates of the first and last sample, and wh ether a system will conduct additional source water monitoring to meet the requirements of §141.701(a). Syst ems must report this information no later than the date the sampling schedule under §141.702 is required.
(2) Systems must report previously collected m onitoring results for grandfathering, along with the associated documentation listed in paragraphs (f)(2)(i) through (iv) of this section, no later than two months after the applicable date listed in §141.701(c).
(i) For each sample result, systems must report the applicable data elements in §141.706.
(ii) Systems must certify that the reported monitoring results include all results the system generated during the time period beginning with the first reported result and ending with the final reported result. This applies to samples that were collected from the sampling location specified for source water monitoring under this subpart, not spiked, and anal yzed using the laboratory's routine process for the analytical methods listed in this section.
(iii) Systems must certify that the samples were representative of a plant's source water(s) and the source water(s) have not changed. Systems must report a description of the sampling location(s), which must address the position of the sampling location in relation to the system's water source(s) and treatment processes, including points of chemical addition and filter backwash recycle.

(iv) For Cryptosporidium samples, the laboratory or laboratories that analyzed the samples must provide a letter certifying that the quality control criteria spec ified in the methods listed in paragraph (c)(1) of this section were met for each sample batch associa ted with the reported results. Alternatively, the laboratory may provide bench sheets and sample examinat ion report forms for each field, matrix spike, IPR, OPR, and method blank sample associated with the reported results.

(g) If the State determines that a previously co llected data set submitted for grandfathering was generated during source water condi tions that were not normal for the system, such as a drought, the State may disapprove the data. Alternatively, the State ma y approve the previously collected data if the system reports additional source water monitoring data, as determined by the State, to ensure that the 

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...data set used under §141.710 or §141.712 represents average source water conditions for the system.
(h) If a system submits previously co llected data that fully meet the number of samples required for initial source water monitoring under §141.701(a) and some of the data are rejected due to not meeting the requirements of this section, systems must conduct a dditional monitoring to replace rejected data on a schedule the State approves. Systems are not requi red to begin this additional monitoring until two months after notification that data have been reje cted and additional monito ring is necessary.


### Disinfection Profiling and Benchmarking Requirements

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### § 141.708 Requirements when making a significant change in disinfection practice.

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(a) Following the completion of initial source water monitoring under §141.701(a), a system that plans to make a significant change to its disinfection practi ce, as defined in paragraph (b) of this section, must develop disinfection profiles and calculate disinfection benchmarks for Giardia lamblia and viruses as described in §141.709. Prior to changing the disinfecti on practice, the system must notify the State and must include in this notice the information in paragraphs (a)(1) through (3) of this section.

(1) A completed disinfection profile and disinfection benchmark for Giardia lamblia and viruses as described in §141.709.
(2) A description of the proposed c hange in disinfection practice.
(3) An analysis of how the proposed change w ill affect the current level of disinfection.

(b) Significant changes to disinfection practice are defined as follows:
(1) Changes to the point of disinfection;
(2) Changes to the disinfectant(s) used in the treatment plant;

(3) Changes to the disinfection process; or
(4) Any other modification identified by the State as a significant change to disinfection practice.


### § 141.709 Developing the disinfection profile and benchmark.

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(a) Systems required to develop disinfection profiles under §141.708 must follow the requirements of this section. Systems must monitor at least weekly for a period of 12 consecuti ve months to determine the total log inactivation for Giardia lamblia and viruses. If systems monitor more frequently, the monitoring frequency must be evenly spaced. Systems that operate for fewer than 12 months per year must monitor weekly during the period of operation. Sys tems must determine log inactivation for Giardia lamblia through the entire plant, based on CT 99.9 values in Tables 1.1 through 1.6, 2.1 and 3.1 of §141.74(b) as applicable. Systems must determine log inactivation for viruses through the entire treatment plant based on a protocol approved by the State.
(b) Systems with a single point of di sinfectant application prior to the entrance to the distribution system must conduct the monitoring in paragraphs (b)(1) through (4) of this section. Systems with more than one point of disinfectant application must conduct the m onitoring in paragraphs (b)(1) through (4) of this section for each disinfection segment. Systems mustmonitor the parameters necessary to determine the total inactivation ratio, using analytical methods in §141.74(a).
(1) For systems using a disinfectant other than UV, the temperature of the disinfected water must be measured at each residual disinfec tant concentration sampling point du ring peak hourly flow or at an alternative location approved by the State.

(2) For systems using chlorine, the pH of the disi nfected water must be measured at each chlorine residual disinfectant concentration sampling point duri ng peak hourly flow or at an alternative location approved by the State.

(3) The disinfectant contact time(s) (t) must be determined during peak hourly flow.
(4) The residual disinfectant concentration(s) (C) of the water before or at the first customer and prior to each additional point of disinfectant applicatio n must be measured during peak hourly flow.
(c) In lieu of conducting new monitoring under paragraph (b) of this section, systems may elect to meet the requirements of paragraphs (c)(1) or (2) of this section.

(1) Systems that have at least one year of existing data that are substantially equivalent to data collected under the provisions of paragraph (b) of this section may use these data to develop disinfection profiles as specified in this section if the system has nei ther made a significant change to its treatment practice nor changed sources since the data were collected. Sy stems may develop disinfection profiles using up to three years of existing data.

(2) Systems may use disinfection profile(s) developed under §141.172 or §§141.530 through 141.536 in lieu of developing a new profile if the system has neither made a signific ant change to its treatment practice nor changed sources since the profile was developed. Systems that have not developed a virus profile under §141.172 or §§141.530 through 141.536 must develop a virus profile using the same monitoring data on which the Giardia lamblia profile is based.

(d) Systems must calculate the total inactivation ratio for Giardia lamblia as specified in paragraphs (d) (1) through (3) of this section. 

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...(1) Systems using only one point of disi nfectant application may determine the total inactivation ratio for the disinfection segment based on either of the methods in paragraph (d)(1)(i) or (ii) of this section.

(i) Determine one inactivation ratio (CTcalc/CT 99.9 ) before or at the first customer during peak hourly flow.
(ii) Determine successive CTcalc/CT 99.9 values, representing sequential i nactivation ratios, between the point of disinfectant application and a point before or at the first customer during peak hourly flow. The system must calculate the total inacti vation ratio by deter mining (CTcalc/CT 99.9 ) for each sequence and then adding the (CTcalc/CT 99.9 ) values together to determine ( Σ (CTcalc/CT 99.9 )).

(2) Systems using more than one point of disinfec tant application before the first customer must determine the CT value of each disinfection segment immediately prior to the next point of disinfectant application, or for the final segment, before or at the first customer, during peak hourly flow. The (CTcalc/CT 99.9 ) value of each segment and ( Σ (CTcalc/CT 99.9 )) must be calculated using the method in paragraph (d)(1)(ii) of this section.
(3) The system must determine the total logs of i nactivation by multiplyin g the value calculated in paragraph (d)(1) or (d)(2) of this section by 3.0.

(4) Systems must calculate the log of inactivation for viruses using a protocol approved by the State.
(e) Systems must use the procedures specified in par agraphs (e)(1) and (2) of this section to calculate a disinfection benchmark.
(1) For each year of profiling data collected and calculated under paragraphs (a) through (d) of this section, systems must determine the lowest mean monthly level of both Giardia lamblia and virus inactivation. Systems must determine the mean Giardia lamblia and virus inactivation for each calendar month for each year of profiling data by dividing the sum of daily or weekly Giardia lamblia and virus log inactivation by the number of values calculated for that month.
(2) The disinfection benchmark is the lowest monthly me an value (for systems with one year of profiling data) or the mean of the lowest monthly mean va lues (for systems with more than one year of profiling data) of Giardia lamblia and virus log inactivation in each year of profiling data.


### Treatment Technique Requirements

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### § 141.710 Bin classification for filtered systems.

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(a) Following completion of the initial round of source water monitoring required under §141.701(a), filtered systems must calculate an initial Cryptosporidium bin concentration for each plant for which monitoring was required. Calculation of the bin concentration must use the Cryptosporidium results reported under §141.701(a) and must follow the procedures in paragraphs (b)(1) through (5) of this section.
(b)(1) For systems that collect a total of at least 48 samples, the bin concentration is equal to the arithmetic mean of all sample concentrations.

(2) For systems that collect a total of at least 24 samples, but not more than 47 samples, the bin concentration is equal to the highest arithmetic mean of all sample concentrations in any 12 consecutive months during which Cryptosporidium samples were collected.
(3) For systems that serve fewer than 10,000 people and monitor for Cryptosporidium for only one year ( i.e. , collect 24 samples in 12 months), the bin concentration is equal to the arithmetic mean of all sample concentrations.
(4) For systems with plants operating only part of the year that monitor fewer than 12 months per year under §141.701(e), the bin concentration is equal to the highest arithmetic mean of all sample concentrations during any year of Cryptosporidium monitoring.
(5) If the monthly Cryptosporidium sampling frequency varies, systems must first calculate a monthly average for each month of monitoring. Systems mu st then use these monthly average concentrations, rather than individual sample concentrations, in the applicable calculation for bin classification in paragraphs (b)(1) through (4) of this section.
(c) Filtered systems must determine their initial bin cl assification from the follo wing table and using the Cryptosporidium bin concentration calculated under par agraphs (a)–(b) of this section:
Bin Classification Table for Filtered Systems



## For systems that are: With a Cryptosporidium bin concentration of . . . 1 

## The bin classification is . . . . . . required to monitor for Cryptosporidiumunder §141.701 Cryptosporidium<0.075 oocyst/L Bin 1.
0.075 oocysts/L ≤ Cryptosporidium<1.0 oocysts/L Bin 2.

1.0 oocysts/L ≤ Cryptosporidium<3.0 oocysts/L Bin 3. 

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...1 Based on calculations in paragraph (a) or (d) of this section, as applicable.

(d) Following completion of the second round of source water monitoring required under §141.701(b), filtered systems must recalculate their Cryptosporidium bin concentration using the Cryptosporidium results reported under §141.701(b) and following the procedures in paragraphs (b)(1) through (4) of this section. Systems must then redetermine their bin clas sification using this bin concentration and the table in paragraph (c) of this section.

(e)(1) Filtered systems must report their initial bin cl assification under paragraph (c) of this section to the State for approval no later than 6 m onths after the system is required to complete initial source water monitoring based on the schedule in §141.701(c).
(2) Systems must report their bin classification underparagraph (d) of this section to the State for approval no later than 6 months after the system is required to complete the second round of source water monitoring based on the schedule in §141.701(c).
(3) The bin classification report to the State mustinclude a summary of source water monitoring data and the calculation procedure used to determine bin classification.
(f) Failure to comply with the conditions of paragraph (e) of this section is a violation of the treatment technique requirement.


### § 141.711 Filtered system additional Cryptosporidium treatment requirements.

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(a) Filtered systems must provide the level of additional treatment for Cryptosporidium specified in this paragraph based on their bin cl assification as determined un der §141.710 and according to the schedule in §141.713.

1 As determined by the State such that the total Cryptosporidiumremoval and inactivation is at least 4.0- log.

2 As determined by the State such that the total Cryptosporidiumremoval and inactivation is at least 5.0- log.

3 As determined by the State such that the total Cryptosporidiumremoval and inactivation is at least 5.5- log.
(b)(1) Filtered systems must use one or more of the treatment and management options listed in §141.715, termed the microbial toolbox , to comply with the additional Cryptosporidium treatment required in paragraph (a) of this section.
(2) Systems classified in Bin 3 and Bin 4 must achieve at least 1-log of the additional Cryptosporidium treatment required under paragraph (a) of this section us ing either one or a combination of the following: bag filters, bank filtration, cartridge filters, chlori ne dioxide, membranes, ozone, or UV, as described in §§141.716 through 141.720.
(c) Failure by a system in any month to achieve treatment credit by meeting criteria in §§141.716 through 141.720 for microbial toolboxoptions that is at least equal to the level of treatment required in paragraph (a) of this section is a viol ation of the treatment technique requirement.
(d) If the State determines during a s anitary survey or an equivalent source water assessment that after a system completed the monitoring conducted under §141.701(a) or §141.701(b), significant changes occurred in the system's watershed that could lead to increased contamination of the source water by Cryptosporidium, the system must take actions specified by the State to address the contamination. These actions may include additional source water monitoring and/or implementing microbial toolbox 

## Cryptosporidium ≥ 3.0 oocysts/L Bin 4.
. . . serving fewer than 10,000 people and NOT required to monitor for Cryptosporidiumunder §141.701(a)(4) NA Bin 1.

If the system bin classification is . . . And the system uses the following filtration treatment in full compliance with subparts H, P, and T of this part (as applicable), then the additional Cryptosporidium treatment requirements are . . . Conventional

filtration treatment (including softening) Direct filtration Slow sand or diatomaceous earth filtration Alternative filtration technologies Bin 1 No additional treatment No additional treatment No additional treatment No additional treatment.
Bin 2 1-log treatment 1.5-log treatment 1-log treatment ( 1 

## )
Bin 3 2-log treatment 2.5-log treatment 2-log treatment ( 2 

## )
Bin 4 2.5-log treatment 3-log treatment 2.5-log treatment ( 3 

## ) 

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...options listed in §141.715.


### § 141.712 Unfiltered system Cryptosporidium treatment requirements.

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(a) Determination of mean Cryptosporidium level. (1) Following completion of the initial source water monitoring required under §141.701(a) , unfiltered systems must calc ulate the arithmetic mean of all Cryptosporidium sample concentrations reported under §141.701(a). Systems must report this value to the State for approval no later than 6 months after th e month the system is required to complete initial source water monitoring based on the schedule in §141.701(c).

(2) Following completion of the second round of source water monitoring required under §141.701(b), unfiltered systems must calculate the arithmetic mean of all Cryptosporidium sample concentrations reported under §141.701(b). Systems must report this value to the State for approval no later than 6 months after the month the system is required to complete the second round of source water monitoring based on the schedule in §141.701(c).
(3) If the monthly Cryptosporidium sampling frequency varies, systems must first calculate a monthly average for each month of monitoring. Systems mu st then use these monthly average concentrations, rather than individual sample concentrations, in the calculation of the mean Cryptosporidium level in paragraphs (a)(1) or (2) of this section.
(4) The report to the State of the mean Cryptosporidium levels calculated under paragraphs (a)(1) and (2) of this section must include a summary of the source water monitoring data used for the calculation.
(5) Failure to comply with the conditions of paragraph (a) of this section is a violation of the treatment technique requirement.
(b) Cryptosporidium inactivation requirements. Unfiltered systems must provide the level of inactivation for Cryptosporidium specified in this paragraph, based on their mean Cryptosporidium levels as determined under paragraph (a) of this section and according to the schedule in §141.713.

(1) Unfiltered systems with a mean Cryptosporidium level of 0.01 oocysts/L or less must provide at least 2-log Cryptosporidium inactivation.
(2) Unfiltered systems with a mean Cryptosporidium level of greater than 0.01 oocysts/L must provide at least 3-log Cryptosporidium inactivation.
(c) Inactivation treatment technology requirements. Unfiltered systems must use chlorine dioxide, ozone, or UV as described in §141.720 to meet the Cryptosporidium inactivation requirements of this section.
(1) Systems that use chlorine dioxide or ozone and fail to achieve the Cryptosporidium inactivation required in paragraph (b) of this section on more than one day in the calendar month are in violation of the treatment technique requirement.
(2) Systems that use UV light and fail to achieve the Cryptosporidium inactivation required in paragraph (b) of this section by meeting the criteria in §141.720( d)(3)(ii) are in violation of the treatment technique requirement.
(d) Use of two disinfectants. Unfiltered systems must meet the combined Cryptosporidium inactivation requirements of this section and Giardia lamblia and virus inactivation requi rements of §141.72(a) using a minimum of two disinfectants, and each of two disinfectants must separately achieve the total inactivation required for either Cryptosporidium, Giardia lamblia, or viruses.


### § 141.713 Schedule for compliance with Cryptosporidium treatment requirements.

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(a) Following initial bin classification under §141.710(c), filtered systems must provide the level of treatment for Cryptosporidium required under §141.711 according to the schedule in paragraph (c) of this section.
(b) Following initial determination of the mean Cryptosporidium level under §141.712(a)(1), unfiltered systems must provide the level of treatment for Cryptosporidium required under §141.712 according to the schedule in paragraph (c) of this section.
(c) Cryptosporidium treatment compliance dates.
Cryptosporidium Treatment Compliance Dates Table

a States may allow up to an additional two years for complying with the treatment requirement for systems making capital improvements.
(d) If the bin classification for a filtered system changes following the second round of source water



## Systems that serve .

. . Must comply with Cryptosporidium treatment requirements no later than . . . a 

## (1) At least 100,000 people (i) April 1, 2012.
(2) From 50,000 to 99,999 people (i) October 1, 2012.
(3) From 10,000 to 49,999 people (i) October 1, 2013.
(4) Fewer than 10,000 people (i) October 1, 2014. 

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...monitoring, as determined under §141.710(d), the sy stem must provide the level of treatment for Cryptosporidium required under §141.711 on a schedule the State approves.

(e) If the mean Cryptosporidium level for an unfiltered system changes following the second round of monitoring, as determined under §141.712(a)(2), and if the system must provide a different level of Cryptosporidium treatment under §141.712 due to this change, the system must meet this treatment requirement on a schedule the State approves.


### § 141.714 Requirements for uncovered finished water storage facilities.

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(a) Systems using uncovered finished water storage fac ilities must comply with the conditions of this section.
(b) Systems must notify the State of the use of each uncovered finished w ater storage facility no later than April 1, 2008.
(c) Systems must meet the conditi ons of paragraph (c)(1) or (2) of this section for each uncovered finished water storage facility or be in compli ance with a State-approved schedule to meet these conditions no later than April 1, 2009.
(1) Systems must cover any uncover ed finished water storage facility.

(2) Systems must treat the discharge from the uncovered finished water storage facility to the distribution system to achieve inactiva tion and/or removal of at least 4-log virus, 3-log Giardia lamblia, and 2-log Cryptosporidium using a protocol approved by the State.
(d) Failure to comply with the requirements of this section is a violation of the treatment technique requirement.


### Requirements for Microbial Toolbox Components

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### § 141.715 Microbial toolbox options for meeting Cryptosporidium treatment requirements.

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(a)(1) Systems receive the treatmen t credits listed in the table in paragraph (b) of this section by meeting the conditions for microbial to olbox options described in §§141.7 16 through 141.720. Systems apply these treatment credits to meet the treatment requirements in §141.711 or §141.712, as applicable.
(2) Unfiltered systems are eligible for treatment cred its for the microbial toolbox options described in §141.720 only.

(b) The following table summarizes options in the microbial toolbox:
Microbial Toolbox Summary Table: Options, Treatment Credits and Criteria



## Toolbox Option Cryptosporidium treatment credit with design and implementation criteria Source Protection and Management Toolbox Options (1) Watershed control program 0.5-log credit for State-approved program comprising required elements, annual program status report to State, and regular watershed survey. Unfiltered systems are not eligible for credit. Specific criteria are in §141.716(a). (2) Alternative source/intake management No prescribed credit. Systems may conduct simultaneous monitoring for treatment bin classification at alternative intake locations or under alternative intake management strategies. Specific criteria are in §141.716 (b).

Pre Filtration Toolbox Options (3) Presedimentation basin with coagulation 0.5-log credit during any month that presedimentation basins achieve a monthly mean reduction of 0.5-log or greater in turbidity or alternative State-approved performance criteria. To be eligible, basins must be operated continuously with coagulant addition and all plant flow must pass through basins. Specific criteria are in §141.717(a). (4) Two-stage lime softening 0.5-log credit for two-stage softening where chemical addition and hardness precipitation occur in both stages.All plant flow must pass through both stages. Singlestage softening is credited as equivalent to conventional treatment. Specific criteria are in §141.717(b). (5) Bank filtration 0.5-log credit for 25-foot setback; 1.0-log credit for 50- foot setback; aquifer must be unconsolidated sand containing at least 10 percent fines; average turbidity in 

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...

### § 141.716 Source toolbox components.

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(a) Watershed control program. Systems receive 0.5-log Cryptosporidium treatment credit for implementing a watershed control program that meets the requirements of this section.

(1) Systems that intend to apply for the watershed contro l program credit must notify the State of this intent no later than two years prior to the treatment compliance date applicable to the system in §141.713.

(2) Systems must submit to the State a proposed watershed control plan no later than one year before the applicable treatment compliance date in §141.713. The State must approve the watershed control plan for the system to receive water shed control program treatment credit. The watershed control plan must include the elements in paragraphs (a)(2)(i) through (iv) of this section.

(i) Identification of an “area of infl uence” outside of which the likelihood of Cryptosporidium or fecal contamination affecting the treatmen t plant intake is not significant. This is the area to be evaluated in future watershed surveys under paragraph (a)(5)(ii) of this section.
(ii) Identification of both potential and actual sources of Cryptosporidium contamination and an assessment of the relative impact of these sources on the system's source water quality.
(iii) An analysis of the effectiveness and feasibility of control measures that could reduce Cryptosporidium loading from sources of contamination to the system's source water.
(iv) A statement of goals and specific actions the system will undertake to reduce source water Cryptosporidium levels. The plan must explain how the acti ons are expected to contribute to specific goals, identify watershed partners and their roles, identify resource requirements and commitments, and include a schedule for plan implementati on with deadlines for completing s pecific actions identified in the plan. 

## wells must be less than 1 NTU. Systems using wells followed by filtration when conducting source water monitoring must sample the well to determine bin classification and are not eligible for additional credit. Specific criteria are in §141.717(c). Treatment Performance Toolbox Options (6) Combined filter performance 0.5-log credit for combined filter effluent turbidity less than or equal to 0.15 NTU in at least 95 percent of measurements each month. Specific criteria are in §141.718(a). (7) Individual filter performance 0.5-log credit (in addition to 0.5-log combined filter performance credit) if individual filter effluent turbidity is less than or equal to 0.15 NTU in at least 95 percent of samples each month in each filter and is never greater than 0.3 NTU in two consecutive measurements in any filter. Specific criteria are in §141.718(b). (8) Demonstration of performance Credit awarded to unit process or treatment train based on a demonstration to the State with a State- approved protocol. Specific criteria are in §141.718(c). Additional Filtration Toolbox Options (9) Bag or cartridge filters (individual filters) Up to 2-log credit based on the removal efficiency demonstrated during challenge testing with a 1.0-log factor of safety. Specific criteria are in §141.719(a). (10) Bag or cartridge filters (in series) Up to 2.5-log credit based on the removal efficiency demonstrated during challenge testing with a 0.5-log factor of safety. Specific criteria are in §141.719(a). (11) Membrane filtration Log credit equivalent to removal efficiency demonstrated in challenge test for device if supported by direct integrity testing. Specific criteria are in §141.719(b). (12) Second stage filtration 0.5-log credit for second separate granular media filtration stage if treatment train includes coagulation prior to first filter. Specific criteria are in §141.719(c) (13) Slow sand filters 2.5-log credit as a secondary filtration step; 3.0-log credit as a primary filtration process. No prior chlorination for either option. Specific criteria are in §141.719(d).

Inactivation Toolbox Options (14) Chlorine dioxide Log credit based on measured CT in relation to CT table. Specific criteria in §141.720(b) (15) Ozone Log credit based on measured CT in relation to CT table. Specific criteria in §141.720(b). (16) UV Log credit based on validated UV dose in relation to UV dose table; reactor validation testing required to establish UV dose and associated operating conditions. Specific criteria in §141.720(d). 

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...(3) Systems with existing watershed control programs ( i.e., programs in place on January 5, 2006) are eligible to seek this credit. Their watershed control pl ans must meet the criteria in paragraph (a)(2) of this section and must specify ongoing and future actions that will reduce source water Cryptosporidium levels.
(4) If the State does not respond to a system regard ing approval of a watershed control plan submitted under this section and the system meets the other requirements of this section, the watershed control program will be considered approved and 0.5 log Cryptosporidium treatment credit will be awarded unless and until the State subsequently withdraws such approval.

(5) Systems must complete the actions in paragraphs (a)(5)(i) through (iii) of this section to maintain the 0.5-log credit.
(i) Submit an annual watershed control program status report to the State. The annual watershed control program status report must describe the system's implementation of the approved plan and assess the adequacy of the plan to meet its goals. It must expl ain how the system is addre ssing any shortcomings in plan implementation, including those previously identified by the State or as the result of the watershed survey conducted under paragraph (a)(5)(ii) of this section. It must also describe any significant changes that have occurred in the water shed since the last watershed sanitary survey. If a system determines during implementation that maki ng a significant change to its approved watershed control program is necessary, the system must notify the State prior to making any such changes. If any change is likely to reduce the level of source water protection, the system must also list in its notification the actions the system will take to mitigate this effect.

(ii) Undergo a watershed sanitary su rvey every three years for community water systems and every five years for noncommunity water systems and submit the survey report to the State. The survey must be conducted according to S tate guidelines and by persons the State approves.

(A) The watershed sanitary survey must meet the followi ng criteria: encompass the region identified in the State-approved watershed control plan as the area of influe nce; assess the implementation of actions to reduce source water Cryptosporidium levels; and identify any significant new sources of Cryptosporidium.
(B) If the State determines that signi ficant changes may have occurred in the watershed since the previous watershed sanitary survey, systems must undergo another watershed sanitary survey by a date the State requires, which may be earlier than the regular date in paragraph (a)(5)(ii) of this section.
(iii) The system must make the watershed control plan, annual status reports , and watershed sanitary survey reports available to the public upon request. These documents must be in a plain language style and include criteria by which to evaluate the success of the program in achieving plan goals. The State may approve systems to withhold from the public porti ons of the annual status report, watershed control plan, and watershed sanitary survey based on water supply security considerations.
(6) If the State determines that a system is not ca rrying out the approved watershed control plan, the State may withdraw the watershed control program treatment credit.
(b) Alternative source. (1) A system may conduct source water monitoring that reflects a different intake location (either in the same source or for an alternate source) or a different procedure for the timing or level of withdrawal from the source (alternative s ource monitoring). If the State approves, a system may determine its bin classification under §141.710 base d on the alternative source monitoring results.
(2) If systems conduct alternative source monitori ng under paragraph (b)(1) of this section, systems must also monitor their current plant intak e concurrently as described in §141.701.

(3) Alternative source monitoring under paragraph (b)(1) of this section must meet the requirements for source monitoring to determine bin classification, as described in §§141.701 through 141.706. Systems must report the alternative source monitoring re sults to the State, along with supporting information documenting the operating conditions under which the samples were collected.
(4) If a system determines its bin classification under §141.710 using alternative source monitoring results that reflect a different intake location or a different procedure for managing the timing or level of withdrawal from the s ource, the system must relocate the intake or permanently adopt the withdrawal procedure, as applicable, no later than the app licable treatment compliance date in §141.713.


### § 141.717 Pre-filtration treatment toolbox components.

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(a) Presedimentation. Systems receive 0.5-log Cryptosporidium treatment credit for a presedimentation basin during any month the process meets the criteria in this paragraph.
(1) The presedimentation basin mustbe in continuous operation and must treat the entire plant flow taken from a surface water or GWUDI source.
(2) The system must continuously add a coagulant to the presedimentation basin.
(3) The presedimentation basin must achieve the performance criteria in paragraph (3)(i) or (ii) of this section.
(i) Demonstrates at least 0.5-log mean reduction of i nfluent turbidity. This reduction must be determined using daily turbidity measurements in the presedime ntation process influent and effluent and must be calculated as follows: log 10 (monthly mean of daily influent turbidity)

− log 10 (monthly mean of daily effluent turbidity).
(ii) Complies with State-approved performance criter ia that demonstrate at least 0.5-log mean removal of micron-sized particulate material through the presedimentation process.
(b) Two-stage lime softening. Systems receive an additional 0.5-log Cryptosporidium treatment credit for a two-stage lime softening plant if chemical addit ion and hardness precipitation occur in two separate and sequential softening stages prior to filtration. B oth softening stages must treat the entire plant flow taken from a surface water or GWUDI source.

(c) Bank filtration. Systems receive Cryptosporidium treatment credit for bank filt ration that serves as 

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...pretreatment to a filtration plant by meeting the criter ia in this paragraph. Systems using bank filtration when they begin source water monitoring under §141.701(a) must collect samples as described in §141.703(d) and are not eligible for this credit.

(1) Wells with a ground water flow path of at least 25 feet receive 0.5-log treatment credit; wells with a ground water flow path of at least 50 feet receive 1.0-log treatment credit. The ground water flow path must be determined as specified in paragraph (c)(4) of this section.
(2) Only wells in granular aquifers are eligible for treatment credit. Granular aquifers are those comprised of sand, clay, silt, rock fragments, pebbles or larger particles, and minor cement. A system must characterize the aquifer at the well site to de termine aquifer properties. Systems must extract a core from the aquifer and demonstrate that in at leas t 90 percent of the core length, grains less than 1.0 mm in diameter constitute at leas t 10 percent of the core material.
(3) Only horizontal and vertical wells are eligible for treatment credit.
(4) For vertical wells, the ground water flow path is the measured distance from the edge of the surface water body under high flow conditions (determined by the 100 year floo dplain elevation b oundary or by the floodway, as defined in Federal Emergency Management Agency flood hazard maps) to the well screen. For horizontal wells, the ground water flow path is the measured distance from the bed of the river under normal flow conditions to the closest horizontal well lateral screen.
(5) Systems must monitor each wellhead for turbidi ty at least once every four hours while the bank filtration process is in operation. If monthly averag e turbidity levels, based on daily maximum values in the well, exceed 1 NTU, the system must report this result to the State and conduct an assessment within 30 days to determine the cause of the high tur bidity levels in the well. If the State determines that microbial removal has been compromised, the State may revoke treatment credit until the system implements corrective actions approved by the State to remediate the problem.
(6) Springs and infiltration galleries are not eligible for treatment credit under this section, but are eligible for credit under §141.718(c).
(7) Bank filtration demons tration of performance. The State may approve Cryptosporidium treatment credit for bank filtration based on a demonstration of performance study that meets the criteria in this paragraph. This treatment credit may be greater than 1.0-log and may be awarded to bank filtration that does not meet the criteria in paragraphs (c)(1)–(5) of this section.

(i) The study must follow a State -approved protocol and must involve the collection of data on the removal of Cryptosporidium or a surrogate for Cryptosporidium and related hydrogeologic and water quality parameters during the full range of operating conditions.

(ii) The study must include sampling both from the production well(s) and from monitoring wells that are screened and located along the shortes t flow path between the surface water source and the production well(s).


### § 141.718 Treatment performance toolbox components.

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(a) Combined filter performance. Systems using conventional filtration treatment or direct filtration treatment receive an additional 0.5-log Cryptosporidium treatment credit during any month the system meets the criteria in this paragraph. Combined fil ter effluent (CFE) turbidity must be less than or equal to 0.15 NTU in at least 95 percent of the measurements. Turbidity must be measured as described in §141.74(a) and (c).

(b) Individual filter performance. Systems using conventional filtrati on treatment or direct filtration treatment receive 0.5-log Cryptosporidium treatment credit, which can be in addition to the 0.5-log credit under paragraph (a) of this section, during any month the system meets the criteria in this paragraph. Compliance with these criteria must be based on indivi dual filter turbidity monitoring as described in §141.174 or §141.560, as applicable.
(1) The filtered water turbidity for each individual filter must be less than or equal to 0.15 NTU in at least 95 percent of the measurements recorded each month.
(2) No individual filter may have a measured tur bidity greater than 0.3 NTU in two consecutive measurements taken 15 minutes apart.
(3) Any system that has received treatment credit for individual filter performance and fails to meet the requirements of paragraph (b)(1) or (2) of this section during any month does not receive a treatment technique violation under §141.711(c) if the State determines the following:
(i) The failure was due to unusual and short-term ci rcumstances that could not reasonably be prevented through optimizing treatment plant design, operation, and maintenance.
(ii) The system has experienced no more tha n two such failures in any calendar year.
(c) Demonstration of performance. The State may approve Cryptosporidium treatment credit for drinking water treatment processes based on a demonstration of performance study that meets the criteria in this paragraph. This treatment credit may be greater than or less than the prescribed treatment credits in §141.711 or §§141.717 through 141.720 and may be awarded to treatment processes that do not meet the criteria for the prescribed credits.
(1) Systems cannot receive the prescribed treatment credit for any toolbox box option in §§141.717 through 141.720 if that toolbox option is included in a demonstration of performance study for which treatment credit is awarded under this paragraph.
(2) The demonstration of performance study must follow a State-approved protocol and must demonstrate the level of Cryptosporidium reduction the treatment process will achieve under the full range of expected operating conditions for the system.
(3) Approval by the State must be in writing and may include monitoring and treatment performance criteria that the system must demonstrate and report on an ongoing basis to remain eligible for the treatment credit. The State may designate such criteria where necessary to verify that the conditions 

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...under which the demonstration of performance credit was approved are maintained during routine operation.


### § 141.719 Additional filtration toolbox components.

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(a) Bag and cartridge filters. Systems receive Cryptosporidium treatment credit of up to 2.0-log for individual bag or cartridge filters and up to 2.5-l og for bag or cartridge filters operated in series by meeting the criteria in paragraphs (a)(1) through ( 10) of this section. To be eligible for this credit, systems must report the results of challenge testing that meets the requirements of paragraphs (a)(2) through (9) of this section to the State. The filters mu st treat the entire plant flow taken from a subpart H
source.
(1) The Cryptosporidium treatment credit awarded to bag or cartridge filters must be based on the removal efficiency demonstrated during challenge testi ng that is conducted according to the criteria in paragraphs (a)(2) through (a)(9) of this section. A factor of safety equal to 1-log for individual bag or cartridge filters and 0.5-log for bag or cartridge fil ters in series must be applied to challenge testing results to determine removal credit. Systems may use results from challenge testing conducted prior to January 5, 2006 if the prior testing was consistent with the criteria specified in paragraphs (a)(2) through (9) of this section.

(2) Challenge testing must be performed on full-scale ba g or cartridge filters, and the associated filter housing or pressure vessel, that are identical in mater ial and construction to the filters and housings the system will use for removal of Cryptosporidium. Bag or cartridge filters must be challenge tested in the same configuration that the system wi ll use, either as individual filters or as a series configuration of filters.

(3) Challenge testing mu st be conducted using Cryptosporidium or a surrogate that is removed no more efficiently than Cryptosporidium. The microorganism or surrogate used during challenge testing is referred to as the challenge particulate. The conc entration of the challenge particulate must be determined using a method capable of discreetly quanti fying the specific microorganism or surrogate used in the test; gross measurements such as turbidity may not be used.
(4) The maximum feed water concentration that can be used during a challenge test must be based on the detection limit of the challenge particulate in the filtrate ( i.e. , filtrate detection limit) and must be calculated using the following equation:

Maximum Feed Concentration = 1 × 10 4 × (Filtrate Detection Limit)
(5) Challenge testing must be conducted at the maximum design flow rate for the filter as specified by the manufacturer.
(6) Each filter evaluated must be tested for a duration sufficient to reach 100 percent of the terminal pressure drop, which establishes the maximum pressure drop under which the filter may be used to comply with the requirements of this subpart.

(7) Removal efficiency of a filter must be determined from the results of the challenge test and expressed in terms of log removal values using the following equation:

LRV = LOG 10 (C f)

− LOG 10 (C p )



### Where:
LRV = log removal value demonstrated during challenge testing; C f 

### = the feed concentration measured during the challenge test; and C p 

### = the filtrate concentration measured during the challenge test. In applying this equation, the same units must be used for the feed and filtrate concentrations. If the challenge particulate is not detected in the filtrate, then the term C p 

### must be set equal to the detection limit.

(8) Each filter tested must be challenged with th e challenge particulate during three periods over the filtration cycle: within two hours of start-up of a new filter; when the pressure drop is between 45 and 55 percent of the terminal pressure drop; and at the end of the cycle after the pressure drop has reached 100 percent of the terminal pressure drop. An LRV must be calculated for each of these challenge periods for each filter tested. The LRV for the filter (LRVfilter ) must be assigned the value of the minimum LRV observed during the three challenge periods for that filter.

(9) If fewer than 20 filters are tested, the overall remova l efficiency for the filter product line must be set equal to the lowest LRV filteramong the filters tested. If 20 or more filters are tested, the overall removal efficiency for the filter product line must be s et equal to the 10th percentile of the set of LRVfiltervalues for the various filters tested. The percentile is defined by (i/(n+1)) where i is the rank of n individual data points ordered lowest to highes t. If necessary, the 10th percentile may be calculated using linear interpolation.
(10) If a previously tested filter is modified in a manner that could change the removal efficiency of the filter product line, challenge testing to demonstrate the removal efficiency of the modified filter must be conducted and submitted to the State.

(b) Membrane filtration. (1) Systems receive Cryptosporidium treatment credit for membrane filtration that meets the criteria of this paragraph. Membrane ca rtridge filters that meet the definition of membrane filtration in §141.2 are eligible for this credit. The level of treatment credit a system receives is equal to the lower of the values determined under paragraph (b)(1)(i) and (ii) of this section.
(i) The removal efficiency demonstrated during cha llenge testing conducted und er the conditions in paragraph (b)(2) of this section.
(ii) The maximum removal efficiency that can be veri fied through direct integrity testing used with the membrane filtration process under the conditions in paragraph (b)(3) of this section.
(2) Challenge testing. The membrane used by the system mustundergo challenge testing to evaluate 

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...removal efficiency, and the system must report the results of challenge testing to the State. Challenge testing must be conducted according to the criteria in paragraphs (b)(2)(i) through (vii) of this section. Systems may use data from challenge testing conducted prior to January 5, 2006 if the prior testing was consistent with the criteria in paragraphs (b)(2)(i) through (vii) of this section.

(i) Challenge testing must be conducted on either a full-scale membrane module, identical in material and construction to the membrane modules used in th e system's treatment facility, or a smaller-scale membrane module, identical in material and similar in construction to the full-s cale module. A module is defined as the smallest component of a membrane unit in which a specific membrane surface area is housed in a device with a filtrate outlet structure.

(ii) Challenge testing must be conducted using Cryptosporidium oocysts or a surrogate that is removed no more efficiently than Cryptosporidium oocysts. The organism or surrogate used during challenge testing is referred to as the challenge particulate. The concentration of the challenge particulate, in both the feed and filtrate water, must be determined using a method capable of discretely quantifying the specific challenge particulate used in the test; gross measurements such as turbidity may not be used.
(iii) The maximum feed water concentration that can be used during a challenge test is based on the detection limit of the challenge particulate in the filtrate and must be determined according to the following equation:

Maximum Feed Concentration = 3.16 × 10 6 × (Filtrate Detection Limit)
(iv) Challenge testing must be conducted under re presentative hydraulic conditions at the maximum design flux and maximum design process recovery specified by the manufacturer for the membrane module. Flux is defined as the throughput of a pressu re driven membrane process expressed as flow per unit of membrane area. Recovery is defined as the volumetric percent of feed water that is converted to filtrate over the course of an operating cycle uninterr upted by events such as chemical cleaning or a solids removal process ( i.e. , backwashing).
(v) Removal efficiency of a membrane module must be calculated from the challenge test results and expressed as a log removal value according to the following equation:

LRV = LOG 10 (C f)

− LOG 10 (C p )



### Where:
LRV = log removal value demonstrated during the challenge test; C f

### = the feed concentration measured during the challenge test; and C p 

### = the filtrate concentration measured during the challenge test. Equivalent units must be used for the feed and filtrate concentrations. If the challenge particulate is not detected in the filtrate, the term C p 

### is set equal to the detection limit for the purpose of calculating the LRV. An LRV must be calculated for each membrane module evaluated during the challenge test.

(vi) The removal efficiency of a membrane filtration process demonstrated during challenge testing must be expressed as a log removal value (LRVC-Test ). If fewer than 20 modules are tested, then LRVCTestis equal to the lowest of the representative LRVs among the modules tested. If 20 or more modules are tested, then LRVC-Testis equal to the 10th perce ntile of the representative LRVs among the modules tested. The percentile is defined by (i/(n+1) ) where i is the rank of n individual data points ordered lowest to highest. If necessary, the 10th perc entile may be calculated using linear interpolation.
(vii) The challenge test must establish a quality c ontrol release value (QCRV) for a non-destructive performance test that demonstrates the Cryptosporidium removal capability of the membrane filtration module. This performance test must be applied to each production membrane module used by the system that was not directly challenge tested in order to verify Cryptosporidium removal capability. Production modules that do not meet the established QCRV are not eligible for the treatment credit demonstrated during the challenge test.
(viii) If a previously tested membrane is modified in a manner that could change the removal efficiency of the membrane or the applicability of the non-des tructive performance test and associated QCRV, additional challenge testing to de monstrate the removal efficiency of, and determine a new QCRV for, the modified membrane must be conducted and submitted to the State.
(3) Direct integrity testing. Systems must conduct direct integrity te sting in a manner that demonstrates a removal efficiency equal to or greater than the removal credit awarded to the membrane filtration process and meets the requirements described in paragr aphs (b)(3)(i) through (vi) of this section. A direct integrity test is defined as a physical test applied to a membrane unit in order to identify and isolate integrity breaches ( i.e. , one or more leaks that could result in contamination of the filtrate).
(i) The direct integrity test must be independently applied to each membrane unit in service. A membrane unit is defined as a group of membrane modules that share common valving that allows the unit to be isolated from the rest of the system for the purpose of integrity testing or other maintenance.
(ii) The direct integrity method must have a resol ution of 3 micrometers or less, where resolution is defined as the size of the smallest integrity breach tha t contributes to a response from the direct integrity test.
(iii) The direct integrity test must have a sensitivity sufficient to verifythe log treatment credit awarded to the membrane filtration process by the State, where sensitivity is defined as the maximum log removal value that can be reliably verified by a direct inte grity test. Sensitivity must be determined using the approach in either paragraph (b)(3)(iii)(A) or (B) of this section as applicable to th e type of direct integrity test the system uses.
(A) For direct integrity tests that us e an applied pressure or vacuum, the direct integrity test sensitivity must be calculated according to the following equation:

LRV DIT = LOG 10 (Q p/(VCF × Q breach ))



### Where:

LRV DIT 

### = the sensitivity of the direct integrity test; Q p 

### = total design filtrate flow from the 

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...

### membrane unit; Q breach 

### = flow of water from an integrity breach associated with the smallest integrity test response that can be reliably measured, and VCF = volumetric concentration factor. The volumetric concentration factor is the ratio of the suspended solids concentration on the high pressure side of the membrane relative to that in the feed water.

(B) For direct integrity tests that us e a particulate or molecular marker, the direct integrity test sensitivity must be calculated according to the following equation:

LRV DIT = LOG 10 (C f)

− LOG 10 (C p )



### Where:

LRV DIT 

### = the sensitivity of the direct integrity test; C f 

### = the typical feed concentration of the marker used in the test; and C p 

### = the filtrate concentration of the marker from an integral membrane unit.

(iv) Systems must establish a control limit within the sensitivity limits of the direct integrity test that is indicative of an integral membrane unit capable of meeting the removal credit awarded by the State.

(v) If the result of a direct integrity test exceeds the co ntrol limit established under paragraph (b)(3)(iv) of this section, the system must remove the membrane unit from service. Systems must conduct a direct integrity test to verify anyrepairs, and may return the membrane unit to service only if the direct integrity test is within the established control limit.
(vi) Systems must conduct direct integrity testing on each membrane unit at a frequency of not less than once each day that the membrane unit is in operation. The State may approve less frequent testing, based on demonstrated proces s reliability, the use of mult iple barriers effective for Cryptosporidium , or reliable proces s safeguards.
(4) Indirect integrity monitoring. Systems must conduct continuous indirect integrity monitoring on each membrane unit according to the criteria in paragrap hs (b)(4)(i) through (v) of this section. Indirect integrity monitoring is defined as monitoring some aspect of filtrate water quality that is indicative of the removal of particulate matter. A system that implemen ts continuous direct integrity testing of membrane units in accordance with the criteria in paragraphs (b)(3)(i) through (v) of this section is not subject to the requirements for continuous indirect integrity moni toring. Systems must submit a monthly report to the State summarizing all continuous indirect integrity monitori ng results triggering direct integrity testing and the corrective action that was taken in each case.
(i) Unless the State approves an alternative para meter, continuous indirect integrity monitoring must include continuous filtrate turbidity monitoring.
(ii) Continuous monitoring must be conducted ata frequency of no less than once every 15 minutes.
(iii) Continuous monitoring mu st be separately conducted on each membrane unit.
(iv) If indirect integrity monitoring includes turbidity and if the filtrate turbidityreadings are above 0.15 NTU for a period greater than 15 minutes ( i.e. , two consecutive 15-minute readings above 0.15 NTU), direct integrity testing must immediately be performed on the associated membrane unit as specified in paragraphs (b)(3)(i) through (v) of this section.

(v) If indirect integrity monitoring includes a State- approved alternative parameter and if the alternative parameter exceeds a State-approved control limit for a period greater than 15 minutes, direct integrity testing must immediately be performed on the associ ated membrane units as specified in paragraphs (b) (3)(i) through (v) of this section.
(c) Second stage filtration. Systems receive 0.5-log Cryptosporidium treatment credit for a separate second stage of filtration that consists of sand, dual media, GAC, or other fine grain media following granular media filtration if the S tate approves. To be eligible for this credit, the first s tage of filtration must be preceded by a coagulation step and both filtra tion stages must treat the entire plant flow taken from a surface water or GWUDI source. A cap, such as GAC, on a single stage of filtration is not eligible for this credit. The State must approve the treatment credit based on an assessment of the design characteristics of the filtration process.

(d) Slow sand filtration (as secondary filter). Systems are eligible to receive 2.5-log Cryptosporidium treatment credit for a slow sand filtration process that fo llows a separate stage of filtration if both filtration stages treat entire plant flow taken from a surface wa ter or GWUDI source and no disinfectant residual is present in the influent water to the slow sand filt ration process. The State must approve the treatment credit based on an assessment of the design characte ristics of the filtration process. This paragraph does not apply to treatment credit awarded to slow sand filtration used as a primary filtration process.

[71 FR 769, Jan. 5, 2006; 71 FR 6136, Feb. 6, 2006]


### § 141.720 Inactivation toolbox components.

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(a) Calculation of CT values. (1) CT is the product of the disinfec tant contact time (T, in minutes) and disinfectant concentration (C, in milligrams per liter). Sy stems with treatment credit for chlorine dioxide or ozone under paragraph (b) or (c) of this section must calculate CT at least once each day, with both C and T measured during peak hourly flow as specified in §§141.74(a) through (b).
(2) Systems with several disinfection segments in s equence may calculate CT for each segment, where a disinfection segment is defined as a treatment unit process with a measurable disinfectant residual level and a liquid volume. Under this approach, systems must add the Cryptosporidium CT values in each segment to determine the total CT for the treatment plant.
(b) CT values for chlorine dioxide and ozone. (1) Systems receive the Cryptosporidium treatment credit listed in this table by meeting the corresponding ch lorine dioxide CT value for the applicable water temperature, as described in paragraph (a) of this section. 

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...CT Values (mg·min/L) for Cryptosporidium Inactivation by Chlorine Dioxide 1

1 Systems may use this equation to determine log credit between the indicated values: Log credit = (0.001506 × (1.09116) Temp ) × CT.
(2) Systems receive the Cryptosporidium treatment credit listed in this table by meeting the corresponding ozone CT values for the applicable water temperature, as described in paragraph (a) of this section.

CT Values (mg·min/L) for Cryptosporidium Inactivation by Ozone 1

1 Systems may use this equation to determine log credit between the indicated values: Log credit = (0.0397 × (1.09757) Temp ) × CT.
(c) Site-specific study. The State may approve alternative chlorine dioxide or ozone CT values to those listed in paragraph (b) of this section on a site-specific basis. The State must base this approval on a site-specific study a system conducts that follows a State-approved protocol.

(d) Ultraviolet light. Systems receive Cryptosporidium, Giardia lamblia, and virus treatment credits for ultraviolet (UV) light reactors by achieving the corres ponding UV dose values shown in paragraph (d)(1) of this section. Systems must validate and monitor UV reactors as described in paragraphs (d)(2) and (3) of this section to demonstrate that they are achievi ng a particular UV dose value for treatment credit.

(1) UV dose table. The treatment credits listed in this table are for UV light at a wavelength of 254 nm as produced by a low pressure mercury vapor lamp. To receive treatment credit for other lamp types, systems must demonstrate an equivalent germicidal dose through reactor validation testing, as described in paragraph (d)(2) of this section. The UVdose values in this table are applicable only to post-filter applications of UV in filtered systems and to unfiltered systems.

UV Dose Table for Cryptosporidium, Giardia lamblia,and Virus Inactivation Credit

(2) Reactor validation testing. Systems must use UV reactors that have undergone validation testing to determine the operating conditions under which the reactor delivers the UV dose required in paragraph (d)(1) of this section ( i.e. , validated operating conditions). These operating conditions must include flow rate, UV intensity as measured by a UV sensor, and UV lamp status.
(i) When determining validated operati ng conditions, systems must account for the following factors: UV absorbance of the water; lamp fouling and aging; measurement uncertainty of on-line sensors; UV dose distributions arising from the velocity profiles throu gh the reactor; failure of UV lamps or other critical system components; and inlet and outlet piping orchannel configurations of the UV reactor.
(ii) Validation testing must include the following: Full scale testing of a reactor that conforms uniformly to the UV reactors used by the system and inactivati on of a test microorganism whose dose response characteristics have been quantified with a low pressure mercury vapor lamp.



## Log credit Water Temperature, °C <=0.5 1 2 3 5 7 10 15 20 25 30 (i) 0.25 159 153 140 128 107 90 69 45 29 19 12 (ii) 0.5 319 305 279 256 214 180 138 89 58 38 24 (iii) 1.0 637 610 558 511 429 360 277 179 116 75 49 (iv) 1.5 956 915 838 767 643 539 415 268 174 113 73 (v) 2.0 1275 1220 1117 1023 858 719 553 357 232 150 98 (vi) 2.5 1594 1525 1396 1278 1072 899 691 447 289 188 122 (vii) 3.0 1912 1830 1675 1534 1286 1079 830 536 347 226 147

Log credit Water Temperature, °C <=0.5 1 2 3 5 7 10 15 20 25 30 (i) 0.25 6.0 5.8 5.2 4.8 4.0 3.3 2.5 1.6 1.0 0.6 0.39 (ii) 0.5 12 12 10 9.5 7.9 6.5 4.9 3.1 2.0 1.2 0.78 (iii) 1.0 24 23 21 19 16 13 9.9 6.2 3.9 2.5 1.6 (iv) 1.5 36 35 31 29 24 20 15 9.3 5.9 3.7 2.4 (v) 2.0 48 46 42 38 32 26 20 12 7.8 4.9 3.1 (vi) 2.5 60 58 52 48 40 33 25 16 9.8 6.2 3.9 (vii) 3.0 72 69 63 57 47 39 30 19 12 7.4 4.7

Log credit Cryptosporidium UV dose (mJ/cm 2 

## ) Giardia lamblia UV dose (mJ/cm 2 

## ) Virus UV dose (mJ/cm 2 

## ) (i) 0.5 1.6 1.5 39 (ii) 1.0 2.5 2.1 58 (iii) 1.5 3.9 3.0 79 (iv) 2.0 5.8 5.2 100 (v) 2.5 8.5 7.7 121 (vi) 3.0 12 11 143 (vii) 3.5 15 15 163 (viii) 4.0 22 22 186 

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...(iii) The State may approve an alternative approach to validation testing.
(3) Reactor monitoring. (i) Systems must monitor their UV reac tors to determine if the reactors are operating within validated conditions, as determin ed under paragraph (d)(2) of this section. This monitoring must include UV intensity as measured bya UV sensor, flow rate, lamp status, and other parameters the State designates based on UV reactor operation. Systems must verify the calibration of UV sensors and must recalibrate sensors in ac cordance with a protocol the State approves.
(ii) To receive treatment credit for UV light, systems must treat at least 95 percent of the water delivered to the public during each month by UV reactors operati ng within validated conditions for the required UV dose, as described in paragraphs (d)(1) and (2) of this section. Systems must demonstrate compliance with this condition by the moni toring required under paragraph (d)(3)(i) of this section.


### Reporting and Recordkeeping Requirements

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### § 141.721 Reporting requirements.

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(a) Systems must report sampling schedules under §1 41.702 and source water monitoring results under §141.706 unless they notify the State that they will not conduct source water mo nitoring due to meeting the criteria of §141.701(d).
(b) Systems must report the use of uncovered finished water storage facilities to the State as described in §141.714.
(c) Filtered systems must report their Cryptosporidium bin classification as described in §141.710.

(d) Unfiltered systems must report their mean source water Cryptosporidium level as described in §141.712.
(e) Systems must report disinfection profiles and benchmarks to the State as described in §§141.708 through 141.709 prior to making a significant change in di sinfection practice.
(f) Systems must report to the State in accordance with the following table for any microbial toolbox options used to comply with treatment requir ements under §141.711 or §141.712. Alternatively, the State may approve a system to certify operation within required param eters for treatment credit rather than reporting monthly operational data for toolbox options.

Microbial Toolbox Reporting Requirements



## Toolbox option Systems must submit the following information On the following schedule (1) Watershed control program (WCP) (i) Notice of intention to develop a new or continue an existing watershed control program No later than two years before the applicable treatment compliance date in §141.713 (ii) Watershed control plan No later than one year before the applicable treatment compliance date in §141.713. (iii) Annual watershed control program status report Every 12 months, beginning one year after the applicable treatment compliance date in §141.713. (iv) Watershed sanitary survey report For community water systems, every three years beginning three years after the applicable treatment compliance date in §141.713. For noncommunity water systems, every five years beginning five years after the applicable treatment compliance date in §141.713. (2) Alternative source/intake management Verification that system has relocated the intake or adopted the intake withdrawal procedure reflected in monitoring results No later than the applicable treatment compliance date in §141.713.
(3) Presedimentation Monthly verification of the following: (i) Continuous basin operation (ii) Treatment of 100% of the flow (iii) Continuous addition of a Monthly reporting within 10 days following the month in which the monitoring was conducted, beginning on the applicable treatment 

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...

## coagulant (iv) At least 0.5-log mean reduction of influent turbidity or compliance with alternative State-approved performance criteria compliance date in §141.713.

(4) Two-stage lime softening Monthly verification of the following: (i) Chemical addition and hardness precipitation occurred in two separate and sequential softening stages prior to filtration (ii) Both stages treated 100% of the plant flow Monthly reporting within 10 days following the month in which the monitoring was conducted, beginning on the applicable treatment compliance date in §141.713.
(5) Bank filtration (i) Initial demonstration of the following: (A) Unconsolidated, predominantly sandy aquifer (B) Setback distance of at least 25 ft. (0.5-log credit) or 50 ft. (1.0-log credit) No later than the applicable treatment compliance date in §141.713.

(ii) If monthly average of daily max turbidity is greater than 1 NTU then system must report result and submit an assessment of the cause. Report within 30 days following the month in which the monitoring was conducted, beginning on the applicable treatment compliance date in §141.713. (6) Combined filter performance Monthly verification of combined filter effluent (CFE) turbidity levels less than or equal to 0.15 NTU in at least 95 percent of the 4 hour CFE measurements taken each month Monthly reporting within 10 days following the month in which the monitoring was conducted, beginning on the applicable treatment compliance date in §141.713. (7) Individual filter performance Monthly verification of the following: (i) Individual filter effluent (IFE ) turbidity levels less than or equal to 0.15 NTU in at least 95 percent of samples each month in each filter (ii) No individual filter greater than 0.3 NTU in two consecutive readings 15 minutes apart Monthly reporting within 10 days following the month in which the monitoring was conducted, beginning on the applicable treatment compliance date in §141.713.]

(8) Demonstration of performance (i) Results from testing following a State approved protocol (ii) As required by the State, monthly verification of operation within conditions of State approval for demonstration of performance credit No later than the applicable treatment compliance date in §141.713. Within 10 days following the month in which monitoring was conducted, beginning on the applicable treatment compliance date in §141.713. (9) Bag filters and cartridge filters (i) Demonstration that the following criteria are met: (A) Process meets the definition of bag or cartridge filtration; (B) Removal efficiency established through challenge testing that meets criteria in this subpart No later than the applicable treatment compliance date in §141.713.

(ii) Monthly verification that 100% of plant flow was filtered Within 10 days following the month in which monitoring was conducted, beginning on the applicable treatment compliance date in §141.713. (10) Membrane filtration (i) Results of verification testing demonstrating the following: (A) Removal efficiency established through challenge testing that meets criteria in this subpart; (B) No later than the applicable treatment compliance date in §141.713. 

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...

### § 141.722 Recordkeeping requirements.

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(a) Systems must keep results from the initial round of source water monitoring under §141.701(a) and the second round of source water monitoring under §141.701(b) until 3 years after bin classification under §141.710 for filtered sys tems or determination of the mean Cryptosporidium level under §141.710 for unfiltered systems for the particular round of monitoring.
(b) Systems must keep any notificati on to the State that they will not conduct source water monitoring due to meeting the criteria of §141.701(d) for 3 years.
(c) Systems must keep the results of treatment moni toring associated with microbial toolbox options under §§141.716 through 141.720 and with uncovered finished water reservoirs under §141.714, as applicable, for 3 years.


### Requirements for Sanitary Surveys Performed by EPA

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## Integrity test method and parameters, including resolution, sensitivity, test frequency, control limits, and associated baseline (ii) Monthly report summarizing the following: (A) All direct integrity tests above the control limit; (B) If applicable, any turbidity or alternative state-approved indirect integrity monitoring results triggering direct integrity testing and the corrective action that was taken Within 10 days following the month in which monitoring was conducted, beginning on the applicable treatment compliance date in §141.713.

(11) Second stage filtration Monthly verification that 100% of flow was filtered through both stages and that first stage was preceded by coagulation step Within 10 days following the month in which monitoring was conducted, beginning on the applicable treatment compliance date in §141.713. (12) Slow sand filtration (as secondary filter) Monthly verification that both a slow sand filter and a preceding separate stage of filtration treated 100% of flow from subpart H sources. Within 10 days following the month in which monitoring was conducted, beginning on the applicable treatment compliance date in §141.713. (13) Chlorine dioxide Summary of CT values for each day as described in §141.720. Within 10 days following the month in which monitoring was conducted, beginning on the applicable treatment compliance date in §141.713. (14) Ozone Summary of CT values for each day as described in §141.720. Within 10 days following the month in which monitoring was conducted, beginning on the applicable treatment compliance date in §141.713. (15) UV (i) Validation test results demonstrating operating conditions that achieve required UV dose (ii) Monthly report summarizing the percentage of water entering the distribution system that was not treated by UV reactors operating within validated conditions for the required dose as specified in 141.720 (d). No later than the applicable treatment compliance date in §141.713. Within 10 days following the month in which monitoring was conducted, beginning on the applicable treatment compliance date in §141.713. 

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### § 141.723 Requirements to respond to significant deficiencies identified in sanitary surveys performed by EPA.

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(a) A sanitary survey is an onsite review of the w ater source (identifying so urces of contamination by using results of source water assessments where available), facilities, equipment, operation, maintenance, and monitoring compli ance of a PWS to evaluate the adequacy of the PWS, its sources and operations, and the distribution of safe drinking water.

(b) For the purposes of this section, a significant defi ciency includes a defect in design, operation, or maintenance, or a failure or malfunc tion of the sources, treatment, s torage, or distribution system that EPA determines to be causing, or has the potential for causing the introduc tion of contamination into the water delivered to consumers.
(c) For sanitary surveys performed by EPA, systems must respond in writing to significant deficiencies identified in sanitary survey reports no later than 45 days after receipt of the report, indicating how and on what schedule the system will address significant deficiencies noted in the survey.
(d) Systems must correct significant deficiencies iden tified in sanitary survey reports according to the schedule approved by EPA, or if there is no approved schedule, according to the schedule reported under paragraph (c) of this section if such d eficiencies are within the control of the system.


### Subpart X—Aircraft Drinking Water Rule

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### Source: 74 FR 53618, Oct. 19, 2009, unless otherwise noted.
§ 141.800 Applicability and compliance date.

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(a) Applicability. The requirements of this subpart consti tute the National Primary Drinking Water Regulations for aircraft that are public water systems and that board only finished water for human consumption. Aircraft public water systems are considered transient non- community water systems (TNCWS). To the extent there is a conflict between the requirements in this subpart and the regulatory requirements established elsewhere in this part, this subpart governs.
(b) Compliance date. Aircraft public water systems must comply, unless otherwise noted, with the requirements of this subpart beginning October 19, 2011. Until this compliance date, air carriers remain subject to existing national primary drinking water regulations.


### § 141.801 Definitions.

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As used in this subpart, the term:

A dministrator means the Administrator of the United States Environmental Protection Agency or his/her authorized representative.

A ir carrier means a person who undertakes directly by l ease, or other arrangement, to engage in air transportation. The air carrier is responsible for ens uring all of the aircraft it owns or operates that are public water systems comply with all provisions of this subpart.

A ircraft means a device that is used or intend ed to be used for flight in the air.

A ircraft water system means an aircraft that qualifies as a public water system under the Safe Drinking Water Act and the national primary drinking water re gulations. The components of an aircraft water system include the water service panel, the filler neck of the aircraft finished water storage tank, and all finished water storage tanks, pipin g, treatment equipment, and plumbing fixtures within the aircraft that supply water for human consumption to passengers or crew.

A ircraft water system operations and maintenance plan means the schedules and procedures for operating, monitoring, and mai ntaining an aircraft water system that is included in an aircraft operation and maintenance program accepted by the Federal Aviati on Administration. (14 CFR part 43, 14 CFR part 91, 14 CFR part 121)

Finished water means water that is introduced i nto the distribution system of a public water system and is intended for distribution and consumption without further treatment, except as treatment necessary to maintain water quality in the distribution system (e.g ., supplemental disinfection , addition of corrosion control chemicals). (40 CFR 141.2)

Human consumption means drinking, bathing, showering, hand washing, teeth brushing, food preparation, dishwashing, and maintaining oral hygiene.

Self inspection means an onsite review of the aircraft water system, including the water service panel, the filler neck of the aircraft finished water stora ge tank; all finished water storage tanks, piping, treatment equipment, and plumbing fixtures; and a review of the ai rcraft operations, maintenance, monitoring, and recordkeeping for the purpose of evaluating the adequacy of such water system components and practices for providing s afe drinking water to passengers and crew.

Watering point means the water supply, methods, and facilities used for the delivery of finished water to the aircraft. These facilities may include water trucks, carts, cabinets, and hoses.


### § 141.802 Coliform sampling plan. 

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(a) Each air carrier under this subpart must devel op a coliform sampling plan covering each aircraft water system owned or operated by the ai r carrier that identifies the following:
(1) Coliform sample collection procedures that are consistent with the requirements of §141.803(a) and (b).

(2) Sample tap location(s) representative of the airc raft water system as specified in §141.803(b)(2) and (b)(4).

(3) Frequency and number of routine coliform sample s to be collected as specified in §141.803(b)(3).
(4) Frequency of routine disinfection and flushing as specified in the operati ons and maintenance plan under §141.804.
(5) Procedures for communicating sample results prom ptly so that any required actions, including repeat and follow-up sampling, corrective action, and notific ation of passengers and crew, will be conducted in a timely manner.
(b) Each air carrier must develop a coliform sampling plan for each aircraft with a water system meeting the definition of a public water system by April 19, 2011.

(c) The coliform sampling plan must be included in the Aircraft Water System Operations and Maintenance Plan required in §141.804. Any subseq uent changes to the coliform sampling plan must also be included in the Aircraft Water System Operations and Maintenance Plan required in §141.804.


### § 141.803 Coliform sampling.

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(a) Analytical methodology. Air carriers must follow the sampling and analysis requirements under this section.
(1) The standard sample volume required for total coliform analysis, regardless of analytical method used, is 100 mL.
(2) Air carriers need determine only the pres ence or absence of total coliforms and/or E. coli ; a determination of density of these organisms is not required.

(3) Air carriers must conduct analyses for total coliform and E. coli in accordance with the analytical methods approved in §141.21(f)(3) and 141.21(f)(6).
(4) The time from sample collection to initiati on of analysis may not exceed 30 hours. Systems are encouraged but not required to hold samples below 10 °C during transit.
(5) The invalidation of a total coliform sample result can be made only by the Administrator in accordance with §141.21(c)(1)(i), (ii), or (iii) or bythe certified laboratory in accordance with §141.21(c) (2).
(6) Certified laboratories. For the purpose of determining compliance with this subpart, samples may be considered only if they have been anal yzed by a laboratory certified by a State or EPA. For the purposes of this paragraph, “State” refers to a State or Tribe th at has received primacy for public water systems (other than aircraft water systems) under section 1413 of SDWA.
(b) Routine monitoring. For each aircraft water system, the sampling frequency must be determined by the disinfection and flushing frequency recommended by the aircraft water system manufacturer, when available, and as identified in the operations and maintenance plan in §141.804.

(1) Except as provided in paragraph (b)(2) of this section, the air carrier must collect two 100 mL total coliform routine samples at the frequency specified in the sampling plan in §141.802 and in accordance with paragraph (b)(3) of this section;

(2) The air carrier may collect one 100 mL total coli form routine sample at the frequency specified in the sampling plan in §141.802 for aircraft with a remov able or portable tank that is drained every day of passenger service, and the aircraft has only one ta p. Aircraft meeting the requirements of this paragraph do not have to comply with paragraph (b)(4) of this section.

(3) Air carriers must perform routine monitoring for total coliform at a frequency corresponding to the frequency of routine disinfection an d flushing as specif ied in the Table b–1 (Routine Disinfection and Flushing and Routine Sample Frequencies). Air carr iers must follow the di sinfection and flushing frequency recommended by the aircraft water system manufacturer, when available. Where the aircraft water system manufacturer does not specify a recommended routine disinfection and flushing frequency, the air carrier must choose a frequency from Table b–1 (Routine Disinfection and Flushing and Routine Sample Frequencies):

Table B–1—Routine Disinfection and Flushing and Routine Sample Frequencies



## Minimum routine disinfection & flushing per

aircraft Minimum frequency of routine samples per

aircraft At least 4 times per year = At least once within every three-month period (quarterly) At least 1 time per year = At least once within every twelve-month period (annually). At least 3 times per year = At least once within every four-month period At least 2 times per year = At least once within every six-month period (semi-annually). 

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...(4) One sample must be taken from a lavatory and one from a galley; each sample must be analyzed for total coliform. If only one water tap is located in the ai rcraft water system due to aircraft model type and construction, then a single tap may be used to collect two separate 100 mL samples.
(5) If any routine, repeat, or follow-up coliform samp le is total coliform-positive, the air carrier must analyze that total coliform-positive culture medium to determine if E. coli is present.
(6) Routine total coliform samples must not be collected within 72 hours after completing routine disinfection and flus hing procedures.
(c) Routine coliform sample results —(1) Negative routine coliform sample results. If all routine sample results are total coliform-negative, then the air carrie r must maintain the routine monitoring frequency for total coliform as specified in the sampling plan in §141.802.
(2) Positive routine E. coli sample results. If any routine sample is E. coli -positive, the air carrier must perform all of the following:
(i) Restrict public access. Restrict public access to the aircraft water system in accordance with paragraph (d) of this section as ex peditiously as possible, but in no case later than 24 hours after the laboratory notifies the air carrier of the E. coli -positive result or discovery of the applicable failure as specified in paragraphs (g) and (h) of this section. All public access restrictions, including applicable public notification requirements, must remain in -place until the aircraft water system has been disinfected and flushed and a complete set of foll ow-up samples is total coliform-negative; and
(ii) Disinfect and flush. Conduct disinfection and flushing in accordance with §141.804(b)(2). If the aircraft water system cannot be physically disconnected or shut-off, or the flow of water otherwise prevented through the tap(s), then the air carrier must disinfect and flush the system no later than 72 hours after the laboratory notifi es the air carrier of the E. coli -positive result or discovery of the applicable failure as specified in paragraphs (g) and (h) of this section; and
(iii) Follow-up sampling. Collect follow-up samples in accordance with paragraph (e) of this section. A complete set of follow-up sample results must be total coliform-negative before the air carrier provides water for human consumption from the aircraft water system and re turns to the routine monitoring frequency as specified in the sampling plan required by §141.802.
(3) Positive routine total coliform sample results. If any routine sample is total coliform-positive and E. coli -negative, then the air carrier must perform at least one of the following three corrective actions and continue through with that action until a complete set of follow-up or repeat samples is total coliformnegative:
(i) Disinfect and flush. In accordance with §141.804(b)(2), conduc t disinfection and flushing of the system no later than 72 hours after the laboratory notifi es the air carrier of the total coliform-positive and E. coli -negative result. After disinfection and flushing is completed, the air carrier must collect follow-up samples in accordance with paragraph (e) of this sect ion prior to providing water for human consumptionfrom the aircraft water system. A complete set of follow-up sample results must be total coliformnegative before the air carrier returns to the routine monitoring frequency as specified in the sampling plan required by §141.802; or
(ii) Restrict public access. In accordance with paragraph (d) of this section, restrict public access to the aircraft water system as expeditiously as possible, but in no case later than 72 hours after the laboratory notifies the air carrier of the total coliform-positive and E. coli -negative result or discovery of the applicable failure as specified in paragraphs (f), (g ), and, (i) of this section. All public access restrictions, including applicable public notification requirements , must remain in-place until the aircraft water system has been disinfected and flushed, and a complete set of follow-up samples has been collected. The air carrier must conduct disinfection and flushing in accordance with §1 41.804(b)(2). After disinfection and flushing is completed, the air carrier must collect follow-up samples in accordance with paragraph (e) of this section prior to providing water for human c onsumption from the aircra ft water system. A complete set of follow-up sample results must be total coliform-negative before the air carrier returns to the routine monitoring frequency as specified in the sampling plan required by §141.802; or
(iii) Repeat sampling. Collect three 100 mL repeat samples no later than 24 hours after the laboratory notifies the air carrier of the routine total coliform-positive and E. coli -negative result. Repeat samples must be collected and analyzed from three taps within the aircraft as follows: The tap which resulted in the total coliform-positive sample, one other lavatory tap, and one other galley tap. If fewer than three taps exist, then a total of three 100 mL samples must be collected and analyzed from the available taps within the aircraft water system.
(A) If all repeat samples are total coliform-negative, then the air carrier must maintain the routine monitoring frequency for total coliform as specified in the sampling plan in §141.802.
(B) If any repeat sample is E. coli -positive, the air carrier must perform all the corrective actions as specified in paragraphs (c)(2)(i), (c)(2)(ii), and (c)(2)(iii) of this section.
(C) If any repeat sample is total coliform-positive and E. coli -negative, then the air carrier must perform the corrective actions spec ified in paragraphs (c)(3)(i) or (c)(3)(ii) of this section, and continue through with that action until a complete set of fo llow-up samples is total coliform-negative.

(d) Restriction of public access. Restriction of public access to the ai rcraft water system includes, but need not be limited to, the following:

(1) Physically disconnecting or shutting off the airc raft water system, where feasible, or otherwise preventing the flow of water through the tap(s);
(2) Providing public notification to pass engers and crew in accordance with §141.805. 

## At least 2 times per year = At least oncewithin every six-month period (semiannually) At least 4 times per year = At least once within every three-month period (quarterly). At least 1 time per year or less = At least once within every twelve-month period (annually) or less At least 12 times per year = At least once every month (monthly). 

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...(3) Providing alternatives to water from the aircraft water system, such as bottled water for drinking and coffee or tea preparation; antiseptic hand gels or wipes in accordance with 21 CFR part 333—“Topical A nti-microbial Drug Products for Ove r-the-Counter Human Use” in the galleys and lavatories; and other feasible measures that reduce or eliminate the need to use the aircraft water system during the limited period before public use of the aircraft water system is unrestricted.

(e) Post disinfection and flushing follow-up sampling. Following corrective action disinfection and flushing, air carriers must complywith post disinfection and flushing follow-up sa mpling procedures that, at a minimum, consist of the following:

(1) For each aircraft water system, the air carrier must collect a complete set of total coliform follow-up samples consisting of two 100 mL total coliform samples at the same routine sample locations as identified in paragraphs (b)(2) and (b)(4) of this section.
(2) Follow-up samples must be collected prior to providing water to the public for human consumption from the aircraft water system.
(3) If a complete set of follow-up samples is total co liform-negative, the air carrier must return to the routine monitoring frequency for total coliform as spec ified in the sampling plan required by §141.802.
(4) If any follow-up sample is E. coli -positive, the air carrier must perform all the corrective actions as specified in paragraphs (c)(2)(i), (c)(2)(ii), and (c)(2)(iii) of this section.

(5) If any follow-up sample is total coliform-positive and E. coli -negative the air carrier must restrict public access to the aircraft water system in accordance with paragraph (d) of this section as expeditiously as possible, but in no case later than 72 hours after the laboratory noti fies the air carrier of the total coliform-positive and E. coli -negative result. All public access re strictions, including applicable public notification requirements, must remain in -place until the aircraft water system has been disinfected and flushed in accordance with §141.804(b )(2) and a complete set of follow-up samples is total coliform-negative. The air carrier must collect follow-up samples in accordance with paragraph (e) of this section. A complete set of follow-up sample results must be total coliform-negative before the air carrier provides water for human consumption from the aircraft water system and returns to the routine monitoring frequency for coliform as specified in §141.802.
(f) Failure to perform required routine disinfection and flushing or failure to collect required routine samples. If the air carrier fails to perform routine disinfecti on and flushing or fails to collect and analyze the required number of routine coliform samples, the air ca rrier must perform all th e corrective actions as specified in paragraph (c)(3)(ii) of this section.
(g) Failure to collect repeat or follow-up samples. If the air carrier fails to collect and analyze the required follow-up samples as a result of an E. coli -positive result, then the air carrier must perform all the corrective actions as specified in pa ragraphs (c)(2)(i), (c)(2)(ii), and (c)(2)(iii) of this section. If the air carrier fails to collect and analyze the required repe at samples or follow-up samples as a result of a total coliform-positive and E. coli -negative result, then the air carrier must perform all the corrective actions as specified in paragraph (c)(3)(ii) of this section.
(h) Failure to board water from a safe watering point (E. coli-positive). For the aircraft water system, the air carrier must perform all the corrective actions specifi ed in paragraphs (c)(2)(i), (c)(2)(ii), and (c)(2)(iii) of this section when it becomes aware of an E. coli -positive event resulting from:
(1) Boarding water from a watering point not in ac cordance with FDA regulations (21 CFR part 1240 subpart E), or

(2) Boarding water that does not meet NPDWRs a pplicable to transient non-community water systems (§§141.62 and 141.63, as applied to TNCWS),
(3) Boarding water that is otherwise determined to be unsafe due to non-compliance with the procedures specified in §141.804(b)(6).
(i) Failure to board water from a safe watering point (non-E. coli-positive). For the aircraft water system, the air carrier must perform all the corrective actions specified in para graphs (c)(3)(ii) of this section when it becomes aware of a non- E. coli -positive event resulting from:
(1) Boarding water from a watering point not in ac cordance with FDA regulations (21 CFR part 1240, subpart E),

(2) Boarding water that does not meet NPDWRs a pplicable to transient non-community water systems (§§141.62 and 141.63, as applied to TNCWS), or
(3) Boarding water that is otherwise determined to be unsafe due to non-compliance with the procedures specified in §141.804(b)(6).


### § 141.804 Aircraft water system operations and maintenance plan.

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(a) Each air carrier must develop and implement an aircraft water system o perations and maintenance plan for each aircraft water system that it owns or operates. This plan must be included in a Federal Aviation Administration (FAA)-accepted air carrier operations and maintenance program (14 CFR part 43, 14 CFR part 91, 14 CFR part 121).
(b) Each aircraft water system operations and maintenance plan must include the following:
(1) Watering point selection requirement. All watering points must be selected in accordance with Food and Drug Administration (FDA) regula tions (21 CFR part 1240, subpart E).

(2) Procedures for disinfection and flushing. The plan must include the following requirements for procedures for disinfection and fl ushing of aircraft water system.
(i) The air carrier must conduct disinfection and flus hing of the aircraft water system in accordance with, or is consistent with, the water s ystem manufacturer's recommendations. The air carrier may conduct disinfection and flushing more frequently, but not less frequently, than the manufacturer recommends. 

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...(ii) The operations and maintenance plan must identi fy the disinfection frequ ency, type of disinfecting agent, disinfectant concentration to be used, and th e disinfectant contact time, and flushing volume or flushing time.

(iii) In cases where a recommended routine disinfection and flushing frequency is not specified by the aircraft water system manufacturer, the air carrier must choose a disinfection and flushing, and corresponding monitoring frequency specified in §141.803(b)(3).
(3) Follow-up sampling. The plan must include the procedures for follow-up sampling in accordance with §141.803(e).
(4) Training requirements. Training for all personnel involved with the aircraft water system operation and maintenance provisions of this regulation must include, but is not limited to the following:
(i) Boarding water procedures;

(ii) Sample collection procedures;
(iii) Disinfection and fl ushing procedures;
(iv) Public health and safety reasons for the requirements of this subpart.

(5) Procedures for conducting self-inspections of the aircraft water system. Procedures must include, but are not limited to, inspection of storage tank, di stribution system, supplem ental treatment, fixtures, valves, and backflow prevention devices.

(6) Procedures for boarding water. The plan must include the following requirements and procedures for boarding water:
(i) Within the United States, the air carrier must board water from watering points in accordance with Food and Drug Administration (FDA) re gulations (21 CFR part 1240, subpart E).
(ii) A description of how the water will be transferred from the watering point to the aircraft in a manner that ensures it will not become contaminated during the transfer.

(iii) A description of how the carrier will ensure th at water boarded outside the United States is safe for human consumption.
(iv) A description of emergency proc edures that meet the requirements in §141.803(h) and (i) that must be used in the event that the air carrier becomes aw are that water was boarded to operate essential systems, such as toilets, but was boarded from a watering point not in accordance with FDA regulations, does not meet NPDWRs applicable to transient no n-community water system s (§§141.62 and 141.63, as applied to TNCWSs), or is otherwise unsafe.

(7) Coliform sampling plan. The air carrier must include the coliform sampling plan prepared in accordance with §141.802.
(8) Aircraft water system disconnect/shut-off, or pr event flow of water through the tap(s) statement. An explanation of whether the aircraft water system can be physically disconnected/shut-off, or the flow of water otherwise prevented through the tap(s) to the crew and passengers.
(c) For existing aircraft, the air carrier must develo p the water system operations and maintenance plan required by this section by April 19, 2011;
(d) For new aircraft, the air carrie r must develop the operations and maintenance plan required in this section within the first calendar quarter of initial operation of the aircraft.

(e) Any changes to the aircraft water system operations and maintenance plan must be included in the FAA-accepted air carrier operations and maintenance program.


### § 141.805 Notification to passengers and crew.

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(a) Air carriers must give public notice for each aircraft in all of the following situations:
(1) Public access to the aircraft water system is restricted in response to a routine, repeat or follow-up total coliform-positive or E. coli -positive sample result in accordance with §141.803(d);
(2) Failure to perform required routine disinfection an d flushing or failure to collect required routine samples in accordance with §141.803(f);

(3) Failure to collect the required follow-up samples in response to a sample result that is E. coli -positive in accordance with §141.803(g);
(4) Failure to collect the required repeat samples or failure to collect the required follow-up samples in response to a sample result that is total coliform-positive and E. coli -negative in accordance with §141.803(g);
(5) In accordance with §141.803(h), the air carrier becomes aware of an E. coli -positive event resulting from water that has been boarded from a watering point not in accordance with FDA regulations (21 CFR part 1240, subpart E), or that does not meet NP DWRs applicable to transient non-community water systems, or that is otherwise determined to be unsafe due to non-compliance with the procedures specified in §141.804(b)(6);
(6) In accordance with §141.803(i), the air carrier becomes aware of a non- E. coli -positive event resulting from water that has been boarded from a watering point not in accordance with FDA regulations (21 CFR part 1240, subpart E), or that doe s not meet NPDWRs applicable to transient noncommunity water systems, or that is otherwise determi ned to be unsafe due to non-compliance with the procedures specified in §141.804(b)(6). 

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...(7) The Administrator, the carrier, or the crew otherwise determines that notification is necessary to protect public health.
(b) Public notification: (1) Must be displayed in a conspi cuous way when printed or posted;
(2) Must not contain overly technical language or very small print;
(3) Must not be formatted in a way that defeats the purpose of the notice;

(4) Must not contain language that nullifies the purpose of the notice;
(5) Must contain information in the appropriate language(s) regarding the importance of the notice, reflecting a good faith effort to reach the non-Engl ish speaking population served, including, where applicable, an easily recognized symbol for non-potable water.
(c) Public notific ation for paragraph (a)(1) of this section must meet the requirements of paragraph (b) of this section in addition to the following:
(1) Public notification must include a prominently displayed, clear statement in each lavatory indicating that the water is non-potable and should not be us ed for drinking, food or beverage preparation, hand washing, teeth brushing, or any other consumptive use; and
(2) A prominent notice in the galleydirected at the crew which includes:
(i) A clear statement that the water is non-potable and should not be used for drinking, food or beverage preparation, hand washing, teeth brushing, or any other consumptive use;
(ii) A description of the violation or situation triggering the notice, including the contaminant(s) of concern;
(iii) When the violation or situation occurred;

(iv) Any potential adverse health e ffects from the violation or situation, as appropriate, under paragraph (g) of this section;
(v) The population at risk, including sensitive subpopulations particularly vulnerable if exposed to the contaminant in the drinking water;
(vi) What the air carrier is doing to correct the violation or situation; and
(vii) When the air carrier expects to return the system to unrestricted public access.
(3) If passenger access to the water system is physica lly prevented through disconnecting or shutting off the water, or the flow of water prevented through the tap(s), or if water is supplied only to lavatory toilets, and not to any lavatory or galley taps, then only the noti ce specified in paragraph (c)(2) of this section is required.
(4) Air carriers must initiate public notification when re striction of public access is initiated in accordance with §141.803(d) and must continue until the aircraft water system is returned to unrestricted public access.
(d) Public notification for paragra phs (a)(2), (a)(4), and (a)(6) of this section must meet the requirements of paragraph (b) of this section in addition to the following:
(1) Public notification must include a prominently displayed, clear statement in each lavatory indicating that the water is non-potable and should not be us ed for drinking, food or beverage preparation, hand washing, teeth brushing, or any other consumptive use; and
(2) A prominent notice in the galleydirected at the crew which includes:
(i) A clear statement that the water is non-potable and should not be used for drinking, food or beverage preparation, hand washing, teeth brushing, or any other consumptive use;
(ii) A clear statement that it is not known whether the water is contaminated because there was a failure to perform required routine disinfection and flushing; or a failure to perform required monitoring; or water was boarded from a watering point not in accord ance with FDA regulations, or that does not meet NPDWRs applicable to transient noncommunity watersystems, or that is otherwise determined to be unsafe due to noncompliance with the proc edures specified in §141.804(b)(6);
(iii) When and where the unsafe water was boarded or when the specific monitoring or disinfection and flushing requirement was not met;
(iv) Any potential adverse health effects from exposure to waterborne pathogens that might be in the water, as appropriate, under paragraph (g) of this section;

(v) The population at risk, including sensitive subpopulations particularly vulnerable if exposed to the contaminant in the drinking water; and
(vi) A statement indicating when the system will be disinfected and flushed a nd returned to unrestricted public access.
(3) If passenger access to the water system is physica lly prevented through disconnecting or shutting off the water, or the flow of water prevented through the tap(s), or if water is supplied only to lavatory toilets, and not to any lavatory or galley taps, then only the noti ce specified in paragraph (d)(2) of this section is required.
(4) Air carriers must initiate public notification when re striction of public access is initiated in accordance with §141.803(d) and must continue until the aircraft water system is returned to unrestricted public access.
(e) Public notification for paragraphs (a)(3) and (a)(5) of this section must meet the requirements of 

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...paragraph (b) of this section in addition to the following:
(1) Public notification must include a prominently displayed, clear statement in each lavatory indicating that the water is non-potable and should not be us ed for drinking, food or beverage preparation, hand washing, teeth brushing, or any other consumptive use; and
(2) A prominent notice in the galleydirected at the crew which includes:
(i) A clear statement that the water is non-potable and should not be used for drinking, food or beverage preparation, hand washing, teeth brushing, or any other consumptive use;
(ii) A clear statement that the water is contaminated and there was a failure to conduct required monitoring; or a clear statement that water is co ntaminated because water was boarded from a watering point not in accordance with FDA regulations, or that does not meet NPDWRs applicable to transient noncommunity water systems, or that is otherwise determined to be unsafe due to noncompliance with the procedures specified in §141.804(b)(6);

(iii) A description of the contaminant(s) of concern;
(iv) When and where the unsafe water was boarded or when the specific monitoring requirement was not met;
(v) Any potential adverse health effects from the situation, as appropriate, under paragraph (g) of this section;
(vi) The population at risk, including sensitive subpopulations partic ularly vulnerable if exposed to the contaminant in the drinking water;
(vii) A statement indicating what the air ca rrier is doing to correct the situation; and
(viii) When the air carrier expects to return the system to unrestricted public access.
(3) If passenger access to the water system is physica lly prevented through disconnecting or shutting off the water, or the flow of water prevented through the tap(s), or if water is supplied only to lavatory toilets, and not to any lavatory or galley taps, then only the noti ce specified in paragraph (e)(2) of this section is required.
(4) Air carriers must initiate public notification when re striction of public access is initiated in accordance with §141.803(d) and must continue public notification until a complete set of required follow-up samples are total coliform-negative.

(f) Public notification for paragrap h (a)(7) of this section must meet the requirements of paragraph (b) of this section in addition to the following:

(1) Notification must be in a form and manner reas onably calculated to reach all passengers and crew while on board the aircraft by using one or more of the following forms of delivery:
(i) Broadcast over public announcement system on aircraft;
(ii) Posting of the notice in conspicuous location s throughout the area served by the water system. These locations would normally be the galleys and in the lavatories of each aircraft requiring posting;

(iii) Hand delivery of the notice to passengers and crew;
(iv) Another delivery method approv ed in writing by the Administrator.
(2) Air carriers must initiate public notification within 24 hours of being informed by EPA to perform notification and must continue notification for the duration determined by EPA.
(g) In each public notice to the crew, air carriers mu st use the following standard health effects language that corresponds to the situations in paragraphs (a)(1) through (a)(6) of this section.

(1) Health effects language to be used when public notice is initiated due to the detection of total coliforms only (not E. coli ) in accordance with paragraph (a)(1) of this section:


### Coliform are bacteria that are naturally present in the environment and are used as an indicator that other, potentially harmful, bacteria may be present. Coliforms were found in [INSERT NUMBER OF SAMPLES DETECTED] samples collected and this is a warning of potential problems. If human pathogens are present, they can cause short-term health effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, and people with severely compromised immune systems.

(2) Health effects language to be used when public notice is initiated due to any E. coli -positive routine, repeat, or follow-up sample in accordance with paragraph (a)(1) of this section:



### E. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term health effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, and people with severely compromised immune systems.

(3) Health effects language to be used when public notice is initiated due to a failure to conduct routine monitoring or routine disinfection and flushing in acco rdance with paragraph (a)(2) of this section; or when there is a failure to conduct repeat or follow-up sampling in accordance with paragraph (a)(4) of this section; or in accordance with paragraph (a)(6) of this section, when the air carrier becomes aware of a non- E. coli -positive event that is the result of water that was boarded from a watering point not in accordance with FDA regulations (21 CFR part 124 0, subpart E), or that does not meet NPDWRs applicable to transient non-community water systems, or that is otherwise determined to be unsafe due to non-compliance with the procedures specified in §141.804(b)(6): 

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...

### Because [REQUIRED MONITORING AND ANALYSIS WAS NOT CONDUCTED], [REQUIRED DISINFECTION AND FLUSHING WAS NOT CONDUCTED] [WATER WAS BOARDED FROM A WATERING POINT NOT IN ACCORDANCE WITH FDA REGULATIONS (21 CR 1240 SUBPART E)], or [OTHER APPROPRIATE EXPLANATION], we cannot be sure of the quality of the drinking water at this time. However, drinking water contaminated with human pathogens can cause short-term health effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, and people with severely compromised immune systems.

(4) Health effects language to be used when public notice is initiated due to a failure to conduct required follow-up monitoring in response to a sample result that is E. coli -positive in accordance with paragraph (a)(3) of this section; or in accordance with paragraph (a)(5) of this section, when the air carrier becomes aware of an E. coli -positive event that is the result of water that was boarded from a watering point not in accordance with FDA regulations (21 CFR part 1240, subpart E), or that does not meet NPDWRs applicable to transient non-community water systems, or that is otherwise determined to be unsafe due to non-compliance with the procedures specified in §141.804(b)(6):


### Because required follow-up monitoring and analysis was not conducted after the aircraft water system tested positive for E. coli, we cannot be sure of the quality of the drinking water at this time. E. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term health effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, and people with severely compromised immune systems.

OR

Water was boarded that is contaminated with E. coli because [WATER WAS BOARDED FROM A WATERING POINT NOT IN ACCORDANCE WITH FDA REGULATIONS (21 CR 1240 SUBPART E)], or [OTHER APPROPRIATE EXPLANATION]. E. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Microbes in these wastes can cause short-term health effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a special health risk for infants, young children, some of the elderly, and people with severely compromised immune systems.
§ 141.806 Reporting requirements.

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(a) The air carrier must comply with the following r equirements regarding reporting of the development of the coliform sampling plan, the operations and main tenance plan, and the disinfec tion and flushing and coliform sampling frequencies.

(1) The air carrier must report to the Administrator that it has developed the coliform sampling plan required by §141.802, which covers each existing airc raft water system, as well as report the frequency for routine coliform sampling identified in the colifor m sampling plan by April 19, 2011. The air carrier must report to the Administrator that it has develope d its operations and maintenance plan required by §141.804 and report the frequency for routine disinfection and flushing by April 19, 2011;

(2) For each new aircraft meeting the definition of an aircraft water system, which becomes operational after publication of this subpart, the air carrier must report to the Administrator that it has developed the coliform sampling plan required by §141.802, as well as report the frequency for routine coliform sampling identified in the coliform sampling plan, wi thin the first calendar quarter of initial operation of the aircraft. The air carrier must report to the Administrator that it has developed the aircraft water system operations and maintenance plan required by §141.804, and report the frequency for routine disinfection and flushing within the first calendar quarter of initial operation of the aircraft.
(b) The air carrier must report the following information to the Administrator:

(1) A complete inventory of aircraft that are public water systems by April 19, 2011. Inventory information includes, at a minimum, the following:
(i) The unique aircraft identifier number;
(ii) The status (active or inactive ) of any aircraft as an aircraft water system as defined in §141.801;

(iii) The type and location of any supplemental treatment equipment installed on the water system; and
(iv) Whether the aircraft water system can be physic ally disconnected or shut-off, or the flow of water prevented through the tap(s).
(2) Changes in aircraft inventory no later than 10 days following the calendar month in which the change occurred. Changes in inventory information include, at a minimum, the following:
(i) Change in the unique identifier number for any newaircraft, or any aircraft removed from the carrier's fleet;

(ii) Change in status (active or inactive) of any ai rcraft as an aircraft water system as defined in §141.801; and
(iii) Change to the type and location of any supplemental treatment equipment added to or removed from the water system.
(iv) Change to whether the aircraft water system can be physically disconnected or shut-off, or the flow of water prevented through the tap(s).
(3) All sampling results no later than 10 calendar days following the monitoring period in which the sampling occurred. The monitoring period is based on the monitoring frequency identified in the coliform sampling plan required under §141.802. Routine disi nfection and flushing even ts must be reported no later than 10 calendar days following the disinfection and flushing period in which the disinfection and 

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...flushing occurred. The di sinfection and flushing per iod is based on the frequency identified in the operations and maintenance plan required under §141.804.

(4) All events requiring notification to passengers or crew, or non-routine disinfection and flushing, or non-routine sampling, within 10 days of the event (e.g., notification of positiv e sample result by laboratory), including information on whether required n otification was provided to passengers or crew or both.
(5) Failure to comply with the monitoring or disinfec tion and flushing requireme nts of this subpart within 10 calendar days of discovery of the failure.
(6) Changes in disinfection and flushing and coliform sampling frequencies no later than 10 days following the calendar month in which the change occurred. Changes to an aircraft's routine coliform sampling frequency and routine disinfection and flushing frequency must be included in the aircraft water system operation and maintenance plan that is incl uded in the air carrier operations and maintenance program accepted by FAA in accordance with §141.804.
(c) The air carrier must provide evidence of a self-inspection to the Administrator within 90 days of completion of the self-inspection required under §141 .808(b), including reporting whether all deficiencies were addressed in accordance with §141.808(c). The ai r carrier must also report to the Administrator within 90 days that any deficiency identified duri ng a compliance audit conducted in accordance with §141.808(a) has been addressed. If any deficiency has not been addressed within 90 days of identification of the deficiency, the report must also include a description of the deficiency, an explanation as to why it has not yet been address ed, and a schedule for addressi ng it as expeditiously as possible.
(d) All information required to be reported to the Administrator under this subpart must be in an electronic format established or a pproved by the Administrator. If an air carrier is unable to report electronically, the air carrier may use an alter native approach that the Administrator approves.


### § 141.807 Recordkeeping requirements.

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(a) The air carrier must keep records of bacteriological analyses for at least 5 years and must include the following information:
(1) The date, time, and place of sampling, and the name of the person who collected the sample;

(2) Identification of the sample as a routine, repe at, follow-up, or other special purpose sample;
(3) Date of the analysis;
(4) Laboratory and person responsib le for performing the analysis;

(5) The analytical technique/method used; and
(6) The results of the analysis.
(b) The air carrier must keep records of any disinfec tion and flushing for at least 5 years and must include the following information:
(1) The date and time of the disinfection and flushing; and

(2) The type of disi nfection and flushing ( i.e. , routine or corrective action).
(c) The air carrier must keep records of a self-inspection for at least 10 years and must include the following information:
(1) The completion date of the self-inspection; and

(2) Copies of any written reports, summaries, or comm unications related to the self-inspection.
(d) The air carrier must maintain sampling plans and make such plans available for review by the A dministrator upon request, includi ng during compliance audits.
(e) The air carrier must maintain aircraft water sys tem operations and maintenance plans in accordance with FAA requirements, and make such plans availa ble for review by the Administrator upon request, including during compliance audits.
(f) The air carrier must keep copies of public notice s to passengers and crew issued as required by this subpart for at least 3 years after issuance.


### § 141.808 Audits and inspections.

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(a) The Administrator may conduct routine compli ance audits as deemed necessary in providing regulatory oversight to ensure proper implementation of the requirements in this subpart. Compliance audits may include, but are not limited to:
(1) Bacteriological sampling of aircraft water system;
(2) Reviews and audits of records as they pertain to water system operations and maintenance such as log entries, disinfection and flushing procedures, and sampling results; and
(3) Observation of procedures involving the handling of finished water, watering point selection, boarding of water, operation, disinfection and flushing, and general maintenance and self-inspections of aircraft water system. 

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...(b) Air carriers or their representatives must perform a self-inspection of all water system components for each aircraft water system no le ss frequently than once every 5 years.

(c) The air carrier must address any deficiency ide ntified during compliance audits or routine selfinspections within 90 days of identification of the defici ency, or where such deficiency is identified during extended or heavy maintenance, before the aircraft is pu t back into service. This includes any deficiency in the water system's design, cons truction, operation, maintenance, or ad ministration, as well as any failure or malfunction of any system component that has the potential to cause an unacceptable risk to health or that could affect the reliable delivery of safe drinking water.


### § 141.809 Supplemental treatment.

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(a) Any supplemental drinking water treatment units installed onboard existing or new aircraft must be acceptable to FAA and FDA; and must be instal led, operated, and maintained in accordance with the manufacturer's plans and specifications and FAA requirements.
(b) Water supplemental treatmen t and production equipment must produce water that meets the standards prescribed in this part.


### § 141.810 Violations.

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A n air carrier is in violation of this subpart when, for any aircraft water system itowns or operates, any of the following occur:
(a) It fails to perform any of the requirements in accordance with §141.803 or §141.804.

(b) It has an E. coli -positive sample in any moni toring period (routine and repeat samples are used in this determination).
(c) It fails to provide notific ation to passengers and crew in accordance with §141.805.
(d) It fails to comply with the reporting and recordkeeping requirements of this subpart.
(e) It fails to conduct a self-inspection or address a deficiency in accordance with §141.808.

(f) It fails to develop a coliform sampling plan in ac cordance with §141.802, or fails to have and follow an operations and maintenance plan, wh ich is included in a FAA accepted program in accordance with §141.804.

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